The Best Seed Starting Mix for a Beginner Vegetable Garden
The image above shows two vanilla marigold plants that were sown on the same day, and they shared much of the same experiences up to just before this image was taken. The dramatic difference in the size of the plants is all because I used two different seed starting mixes.
I previously posted about my plans to start a vegetable garden this year. I have planted flower seeds, and a few years ago I had some small basil plants, but I have never grown vegetables before.
Some vegetables can be directly sown outdoors, in the ground or in potting mix, but others can really benefit from a head-start indoors, especially if you live in a more northern climate that has a shorter growing season.
So, I sought to start some plants indoors, mainly cucumber seeds and hot peppers, but also basil and some marigolds. I figure I’ll pick up a tomato plant or two locally, and will sow carrots and dill directly outdoors. Depending on this year goes, I might change things up next year.
What I kept reading online and seeing in videos is that 1) seed starting mix is largely lifeless, and that 2) seedlings don’t need fertilizers or nutrients. I… got things wrong, and learned differently.
I ordered two kinds of seed starting mix online, and they arrived just before my first seed packets arrived. Some ToolGuyd readers seemed interested in this kind of topic, or might be interested in the future. After seeing differences in the first batch of seedlings, I later ordered two more brands to try out.
See? The plants on the right were stunted, even early on, while the ones on the left thrived and grew at a steady pace.
I decided to run a simple experiment, to see which of 4 seed starting mixes yielded the best results.
Seed Starting Mixes
From left to right:
- Gardener’s organic seed starting mix
- Bio-Blended Compost (composted manures and plant materials), sphagnum peat moss, perlite, mineral and nutrient amendments
- 95% coconut fiber, perlite, fertilizer (0.06 – 0.03 – 0.03)
- 60-70% sphagnum peat moss, vermiculite, coir pith, and lime for pH adjuster
- 80-90% Canadian sphagnum peat moss, perlite, limestone to adjust pH, and yucca extract
- Active ingredients: Ectomycorrhizal Fungi, total of 131.38 propagules/cc, Endomycorrhizal Fungi, total of 0.072 propagules/cc
You can also make your own seed starting mix, and there is no shortage of recipes online. However, smaller bags of raw materials are not very economical, and you need to plan on sowing a lot of seedlings to make good use out of a big batch of DIY seed starting mix. This might be a path I explore next year, but for now, I’m happy at the convenience of using premade mix, spending a little more for the convenience.
General Seed Mix Notes
Gardener’s: This starting mix more resembled potting mix, with bits of wood chips, and even a pebble or two. It wasn’t until after I wrote up my first post that I realized it has some composted manures. I probably would have avoided this for indoors use, but there haven’t been any issues yet.
Some of the cells filled with Gardener’s mix grew fuzzy white mold that was easily scraped off. Some of the plants developed green algae on the surfaces due to moisture.
I learned to use less water when sowing my seeds, and things worked out better.
After starting some plants with both Gardener’s organic and Burpee mixes, I preferred the Burpee for its ease of use and faster germination rate, but the Gardener’s won out later.
The Gardener’s organic mix proved to be the best overall. Their non-organic mix is cheaper and said to be finer. I have a bag of that on order but haven’t received it yet.
Generally, you shouldn’t need a whole lot of seedling mix, but cucumbers don’t like their roots to be disturbed and so it’s best to start those in larger pots, and that requires more mix.
Burpee: I liked the Burpee mix for its easier use, It’s supposed to have some plant food mixed in, but it didn’t do much for any of my plants past initial germination. The Burpee mix seemed to allow for faster germination.
It’s hard to comment confidently about germination rates because there are too many factors at play. Maybe one mix was moister? Maybe it was more compressible and allowed for greater seed contact?
Jiffy: The Jiffy mix seems to be a great choice, and will likely be one of my top two picks in the future. It’s a pain to work with though, since it’s fluffy and near bone-dry in the packaging and requires more hydration before use than the other mixes. The Jiffy mix was somewhat spongy, which I did not like.
Espoma: I had high hopes for the Espoma mix, given that the brand is very experienced with plant nutrient amendments and potting mixes. But, the Espoma seems to be performing the worst. The Espoma mix also seemed to be a little more spongier. It was hard for me to find a balance between “moist” and “soggy,” but things might have been better if I moistened the mix and then left it to sit a bit longer.
I read in a couple of places that seed starting mix should (could) be sterilized with boiling water prior to use. I did not do this, but I might give it a try next year to see if it helps with things like fuzzy white mold or algae growth.
Also, I have now started mixing in worm castings with my starting mixes, to give them some organic matter. I’m not sure what else I would be comfortable adding at the start – definitely not compost or other materials typically intended for outdoors use.
I figure that the Gardener’s mix, and its compost and plant materials, is treated during production, and I’ve had no issues with it so far.
The brand of worm castings I found has two grades – standard and premium at a 50% higher cost. I went with the premium product as I read it’s sieved to a finer size, which seems more desirable for indoors and seed mix use. Indeed, it has the consistency of coarse sand. Here it is on Amazon, and I’ll also include a link to it at the end of the post.
You’ll see in a bit why I’m talking about seedling nutrition, because I learned some things I wish I knew one month ago.
Testing and Results
Here’s another image of all four mixes. I loaded (4) 6-cell trays, each with mix that was moistened and then compacted. After the seeds were sown, each cell was placed in a tray filled with shallow water to ensure that the mixes were all fully hydrated. With bottom watering, the water is seeped up through holes in the bottom of the tray.
Some of the mixes, namely the Gardener’s, needs to be sprayed with a little water from above after the seeds sprout, otherwise it seems to form a hard and dry crust.
After this batch of seedlings sprouted and joined my other seedlings under grow lights, I watered them the same and also applied some liquid-soluble seedling fertilizer.
Seedlings do need far lower nutrient levels than larger plants, and so you have to be careful to avoid over-fertilizing them. But they also won’t grow much if you don’t give them any nutrients. I’ll get to that in a bit.
For the experiment, I sowed Sugar Rush Peach hot pepper seeds. These were all sown on 4/18/20, and so the photos taken today reflect seedlings
Here’s what the seedlings look like today. They all received the same water, and the same fertilizer treatments.
There were two applications of liquid-soluble seedling fertilizer – a little less than 3mL was added to each cell on 4/26 – a few days after they all sprouted, and they were bottom-watered with fertilizer-water mix on 5/2.
That first application of fertilizer was a mistake. I had forgotten that the new sprouts were mixed into my other small seedlings which were supposed to get fertilizer, and so I had already given 3mL to one tray of seedlings before realizing this. So, I gave the same to all of the others as well.
Everything I read about applying liquid fertilizer is meant for top-watering applications. Since I bottom-water, I tried giving a set amount of liquid fertilizer to the plants from the top. I started with 5mL using a syringe, and then went to using a 3mL disposable pipette. Smaller seedlings received a full 3mL, or less if they were really small or alone in the cell, and double that for larger plants.
But, my last fertilization trial, where I bottom-watered with a fertilizer-water mix at the correct proportions, seemed to work out well, and so I’ll likely do this again in the future unless or until I learn otherwise.
This upcoming weekend, the smaller plants will receive seedling fertilizer and the larger ones will receive something a little different. I used a different fertilizer at double seedling strength but half general directions strength last week on a different set of hot pepper plants, and that seems to be a good plan for these.
I had formed fertilizer and nutrient plans for when the plants go outside, but my seedling plans required more response and learning as I go along. I did have the water-soluble seedling fertilizer powder from the start, and probably should have been using it from the start and in greater amounts than my first attempts to fix things. Then again, if I had done that, I wouldn’t have learned much.
In the following images, I’ll be going in a different order than how I described things above. The order here is from best to lowest performance.
Gardener’s Seed Starting Mix Results
So this is one cell’s worth of the seedlings that were sown in the Gardener’s organic mix. It was transplanted into this pot on 5/4, and so it has spent a few days in slightly different conditions than the smaller seedlings.
Here’s a photo of how things looked previously. The seedlings in the Gardener’s mix are at the top of the photo. There is a cell without any germination – either that seed was a dud, or I forgot to sow one there.
Jiffy Seed Starting Mix Results
Here’s a transplanted seedling that was started in Jiffy mix. It was transplanted on 5/6.
These seedlings weren’t quite ready for transplant, but I was concerned they were getting root-bound. I don’t understand why, but all of these hot pepper seedlings would close their leaves a bit during the day, in a V-shaped formation where it almost looked like they were praying. None of my other seedlings did this except towards night time.
The plants were being fed, and they didn’t have signs of under- or over-watering – that I know of – and so I thought I’d see if they improve if transplanted to larger pots.
Here are the 3 remaining seedlings that were sown in Jiffy seed starting mix. Yes, I know that I have scrape the algae growth off the surface. Or, it’ll be covered up and the problem eliminated – I think so at least – when I transplant the seedlings into a bigger pot.
Sorry, in case I confused anyone, any mention of “transplant” in this post refers to my potting-up the seedlings. My mid-sized pots are still delayed (I ordered them 3 weeks ago), and so I had to go directly from seedling cells to 4″ pots. Some smaller seedlings, such as when a larger seedling shares a cell with a much smaller one, have gone into 3″ Jiffy pots – the kind that can be directly transplanted and buried into a larger pot when ready.
Burpee Seed Starting Mix Results
Next, here are the seedlings that were started in Burpee mix.
The Burpee mix saw lots of germinations. I had limited seeds, and so if you see a centered plant, it was the sole seed sown in that space. Here, I think all but one seed successfully germinated, with the dud being in the
8pm location of the first cell at the top.
These seedlings appear healthy, but they’re growing slower than all the other seedlings.
The Burpee is supposed to have some fertilizer – what’s going on here? On the bright side, the Burpee mix was the easiest to work with, as it required less moisture to hydrate the starting mix out of the bag.
Espoma Seed Starting Mix Results
The Espoma seed starting mix proved to be the worst. I did transplant two seedlings, to see if it would help to get them into a more nutrient-rich mix.
It’s supposed to have “Myco-tone” and plant-beneficial fungi, but what I’m seeing is poor germination success and the slowest growing sprouts.
There is a bright side – the Espoma mix seemed easiest to free loose seedlings from, and so I’d pick this in the future if or when I want to try basic hydroponics techniques. Or rather, I’d be able to use up the remainder of the two bags I bought.
With Respect to Performance:
- Gardener’s Organic Mix
- Jiffy Organic Mix
- Burpee Organic Mix
- Espoma organic Mix
With Respect to Ease of Use:
- Burpee Organic Mix
- Gardener’s Organic Mix
- Jiffy Organic Mix
- Espoma Organic Mix
Additional Examples and Observations
Here’s the image of my vanilla marigolds again. These were sown on 4/8/20.
Ah, so what’s going on here? The cells at the left, which I’ll call 1 and 2, received one application of fertilizer. Cells 3, 4, and 6 all received 2 applications of fertilizer. Cell 5 received 3 applications of fertilizer.
There’s no “nutrient burn,” and you can see the dramatic differences in results.
More nutrients = more growth.
This image was not from today, it was from maybe two weeks ago. Yes, they were all sown on the same day, 4/5/20.
Here’s a more recent image of one of the previously nutrient-deficient basil plants. It’s doing okay. In case you couldn’t tell, the B in the image denotes the Burpee starting mix.
I have not been running strict controls, or taking close notes, but still tried to keep track of things.
Here’s where things get interesting. On the left are basil plants that were started in a coir pot on 4/24/20. These seeds were from a different supplier and could be a slightly different species, I don’t know.
On the right are the basil plants in the Burpee mix that were sown on 4/5/20.
I also have a 6-cell batch of basil seedlings from 4/25 that I mistakenly sown into “transplant” mix. Despite having more organic matter and worm castings, those seedlings haven’t grown quite as big as these.
Basil sown in a mix of Jiffy seedling mix and worm castings on 4/24 have outgrown many of the seedlings grown in Burpee mix on 4/5.
Nutrients can get a seedling or plant back to health and good growth, but it won’t make up for lost time.
With some plants such as tomatoes and hot peppers requiring 6-8 weeks indoors before being planted outdoors, and some hot peppers having length germination periods, timing and steady growth is very important.
I’m kicking myself for not realizing how important seed starting mix and added nutrients can be, but I’m happy I was able to realize there was a different.
To speak candidly, I might not be on the right track yet when it comes to seedling fertilizer and nutrient application rates. But, I hope I’m somewhat close. I’ll be experimenting a bit more as the season progresses, and will hopefully learn a little more that I can put to use in next year’s season-prep efforts.
Here are what some of my jalapeno seedlings looked like in the last week of April.
Some of my plants had yellow leaves, others were turning black. But, none of this was happening to the plants that were sown in the Gardener’s Organic mix.
Were they over-watered? Too little added nutrients?
Adding a couple of mL of mixed fertilizer wasn’t doing much to save these seedlings. Soaking the trays in the mixed solution, basically bottom-watering all the seedlings in the proportionally mixed fertilizer – that definitely seems to have helped.
My petunias, lower left of this image, started off with tiny and dark purple leaves. After seeing fast and successful French marigold and basil germinations in the Burpee mix, I mistakenly declared it to be superior, and so I used it for my only 6 cells of pelleted purple petunias. It is crazy how well adding sufficient nutrients was able to liven them up and fuel growth.
Here, you can see the still-yellow leaves of some of my jalapeno seedlings. While their first leaves (cotyledon) are still yellow, their true leaves are coming in nice and green now.
I think these plants are recovering nicely, don’t you? They’re far too small to be able to grow and strength up for transplanting outside for the season, but maybe I’ll still plant them in the ground either as an experiment or sacrificial easier-access plants in case of hungry animals.
Things looked dire for these seedlings, but they do seem to have bounced back.
Before I write any more, one more thing to mention is that the Gardener’s mix resulted in zero “helmet heads,” a condition that arises when a hot pepper seeding cannot properly separate from its shell, as it’s a denser mix. I saw more “helmet heads” – especially habanero plants, when I didn’t sow them deeply enough. All but two of the helmeted seedlings survived, some needing help to gently coax their first leaves out.
There are a lot of different factors involved with selecting a seed starting mix.
I was worried about fungus gnats, which is why some recommend that starting mix be sterilized prior to use, but don’t seem to have developed any problems. There were 2 or 3 bugs this week, but they could have been fruit flies, I don’t know.
Of these brands, Gardener’s organic mix was the best choice. It provided the best environment for the healthy growth of my plants, which is perhaps the most important characteristic. The Burpee mix was easier to use, and resulted in slightly faster germination, but I didn’t add nutrients fast enough and my plants suffered for it.
Jiffy and Espoma mixes were harder to use. I haven’t calculated the economics of the different mixes, but it definitely seems that you get more per quart with Gardener’s and Burpee mixes than Jiffy and Espoma. The better two mixes were easier to work with, and the other two drier and fluffier, requiring more prep efforts.
For next year, I’ll likely stick with Gardener’s organic mix, and perhaps Jiffy as a close second choice.
I just sowed a second round of cucumber plants in Jiffy mix with worm castings mixed in, and it doesn’t feel heavy enough. With other plants, you can remove the loose mix and the roots will adjust just fine in their new home. However, I keep reading that cucumbers really don’t like their roots disturbed, and that even direct-sowing is preferable if the growing season is long enough.
With Gardener’s mix though, if you have two seedlings in a cell and want to separate them, good luck – you’re going to have a very difficult time of it without traumatizing your plants.
But with the looser mixes – pretty much all the other mixes I tried – it’s possible to separate seedlings for separate transplant.
I’m just going to have to see how things go.
Also, I still have plenty of supplies and could start over with a more scientific approach and added controls and even greater variables, but there has to be a lot of interest for me to do that.
This was my first time trying to grow anything from seed, and I wasn’t aware of how different things can turn out.
The Espoma mix especially disappoints me. It’s advertised as being an enhanced “rich, premium blend of the finest natural ingredients.” That is not what I have seen so far. It seems that their mix used to have earthworm castings in it, but it doesn’t anymore, which could explain why it performed so poorly.
The Burpee mix is supposed to have some fertilizer, but then why did it perform a little worse than the Jiffy mix that has nothing of the sort added?
A lot of this make sense – of course plants need nutrients to grow! My previous container-planting endeavors were with Miraco-Gro, and all I needed to add were flower seeds, water, and protection against animals who liked to decimate anything that tried to grow.
I hope you found this post to be helpful – please let me know. I threw a lot of information and details at you here, and if there’s interest I’ll tighten up the sections and republish a more formal write-up.
I wish I could send a link to this post to a one-month-younger me, but I can’t. Hopefully this will save some of you from making the same mistakes I did.
Supplies I Used
Seed Starting Mixes
Fertilizers and Nutrients
Other Seed-Starting Supplies
- 1020 trays, humidity dome, 6-cell trays: via Bootstrap Farmer, via Bootstrap Farmer on Amazon – I like this one better (so that I don’t make too much of a mess in the kitchen when sowing seeds) – I use a larger rack I already have, but smaller ones could work too – I use smaller containers for smaller mixes, and the 6 quart has been great for larger quantities
I ordered all of the seed-starting supplies from Amazon, except the Bootstrap Farmer supplies, which I ordered from their website directly.
Please keep in mind that I’m still learning about all this, but don’t hesitate to ask if you think there’s something I can help you with.
Wow that is very interesting seeing the difference in growth. Thank you for the specifics.
“The Best Seed Staring Mix…”
Don’t you know, a watched seed never grows?!
As someone that long ago managed a greenhouse, I have always used Jiffy brand. Once tried another mix that had wood products in it (are they mandated by law for soils?), and was not impressed. I could not find Jiffy and I was in a rush, but the wood stuff just bothered me and made it even more difficult to sow seeds. Yes, Jiffy is difficult to wet but it works fine once I get it wet. Don’t know why they do not include a wetting agent like many other soil mixes include (Including my favorite potting soil Pro-Mix BX)
As for fertilizer, I have always been lazy at home applying it in the water in the basin of seedlings and not top application. Gets to the plants regardless in my mind.
I think the idea behind wood products is that it provides a little moisture retention and prevents compaction. Or maybe it’s just a cheap scrap material that has to go somewhere.
Remembering your earlier comment about Pro-Mix BX (thank you!), I bought a package at the local garden center, and then another one in case I don’t come across it again this season. I’ll be comparing it to Espoma and Gardener’s products. I like the compactness of the Pro-Mix.
I had tried looking for it previously online, but shipping costs were understandably high, and I couldn’t easily find information about where to get it locally. Background researched showed that Pro-Mix is pretty universally favored, but I opted for more easily available alternatives, not knowing it would be available locally, and not knowing if I would be able to visit different stores in the area to find it (given the current state of pandemic restrictions).
Seeing what I learned now, I think that next year I might go with Jiffy for everything except cucumbers, which will be Gardener’s, as it’s more representative of what the final outdoor mix will look like. Plus, it performed quite well so far with respect to plant growth and health.
Our local Wal-Mart carries Pro-Mix in half bale versions, albeit not the HP version. I usually get the HP version from the single local garden center that carries the full 3.8 cu ft bales, supporting a local business when I can as a bonus.
Great extra topic for ToolGuyd.
I was excited when the testing segment started and hoped for a series of overhead shots every few days of those 4x 6-cell trays, and things remaining side by side in the same order … but it got a bit hard to follow and decipher.
I appreciate the testing and will keep the ranking in mind … even if we don’t get started on a veggie garden this year. Had snow again. Another cold week coming up. Lots to do.
Honestly, things got as messy here as it seems. I took some photos along the way, but I couldn’t spare the time for steady progress photos. I took separate photos at the end, and along the way there were some “I’ve got to record that future future reference moments.”
This was more of a “proof of concept” experiment, needed to establish controls for a sturdier comparison.
My shelves should start emptying after plants start heading outside, and I can spent the time to do things properly – and with less train of thought commentary now that I got it all out of my system.
But to do any of that, I needed to gauge whether there’s interest in it.
I don’t know if I have enough hot pepper seedlings to experiment with, but I have plenty of basil left.
It’s been cold here too, and if I’m lucky I can start hardening off some of my plants starting Wednesday or so.
Concur with Frank’s criticism. I discerned a disorganized application of The Scientific Method, comparable to a middle-of-the-road project at a middle school science fair. I would scold a high school student who submitted such.
Is that your way of promoting for a redo?
Everything was hastened for expediency – both for my plants, and to get raw/informal conclusion in time to make a difference. Extra time in preparation means it could come too late for anyone still seeding indoors for this season.
The Scientific Method was absolutely disregarded here. There was no time for it. This also serves as a prelude to round 2, where it’s less important to get the seeds sown and grown for this year and more important to explore what would be beneficial for next year.
Adding in controls and data collection of the level I could and perhaps should have implemented would have taken too much time and effort for this round.
For instance, a more controlled set-up would require weighing each mix at the start, measuring out the water, doing regular weigh-ins, watering each separate tray individually to measure water intake, taking daily photos, rotating cells and positions to ensure uniform lighting or at least eliminate any influences due to potential hot spots, and so forth.
I can do all of that and more, but it would require much more active experimentation data collection, much more planning, time, and effort. That’s not something I was willing to commit to when I didn’t even know what differences there could be, and mostly because I didn’t know if there would be any interest here.
In other words, sorry, not sorry.
Sure shows the importance of nutrients. Side note: Amazon has the Dewalt DCW201B 20v Sander for $93.00, with free shipping.
It would have been interesting, if plain soil was used also. Maybe plain soil, and plain soil with nutrients. See how it compares to the commercial starting mixes. Both in performance, and if weed seeds are any problem.
Soil might work well outdoors, but is not very good for starting seeds indoors.
Soil is highly recommend against for potting mixes as well, due to it being too dense and poor draining.
It seems to be near universally agreed upon that sphagnum peat moss or coco coir are the best choices for “indoors” seed germination, whether the seedlings go into potting mixes or the ground.
Soil also varies depending on location. A bag of topsoil from the home center is good for filling in holes and low points in landscaping, or even for mixing into a ground garden space, but just wouldn’t work well for seed germination.
Seed starting mixes typically have perlite for reduced compaction and better drainage, and stuff for various reasons.
You can make your own starting mix, and there are no shortage of recipes out there, but it requires more materials and effort. It’s something I might try in the future for better economics.
The starting mix with composted material and organic components mixed in did the best, but right now I’m also seeing decent results with starting mix that has worm castings and with nutrients regularly supplied via fertilizer/plant food.
The basil I started on 4/24 and 4/25 is now larger than the basil I started on 4/5. The earlier-sown basil appears to have recovered mostly.
When it comes to growth, soil vs. container potting mixes is difficult to compare. Soil doesn’t work well in containers, containers need more watering and attention, and in soil plants have near-unlimited potential to spread out whereas there are hard or soft walls in container planting.
I have used my own garden soil in the past, with very good results. But i only started tomatoes. So I tend to think the soil mixes are a bit overrated, and a lot of the information out there jilted by comercial companies. But everyone’s soil varies, so for consistent results the soil mixes are a good idea. But I would suggest that people use both, their own soil & comercial mix. They may not need to buy the comercial mix in the future, if their soil works for them. Granted, we are not talking a big expense.
Very interesting to follow your progress.
I’m making process towards custom beds. I initially thought about taking plastic corrugated roofing sheets but found that they weren’t nearly as rigid as the corrugated steel, so I got 10′ sheets of steel instead.
By the way, there’s a typo in the title. (Starting vs staring).
Corrugated roofing sheets seems to be a popular way to go.
I have room for raised gardens, but no clue as to where I want them to go, hence doing everything in containers this year.
Check out Costco for the same GE grow lights but at almost half the cost and costco’s awesome return policy:
I haven’t bought those, but I did buy the Feit LED grow lights that costco sold a few years ago that are the same as the ones you posted, but had 4 bulbs and a reflector on the back for $60 (Then clearanced at $30!)
I’m using one of the feits for sunflowers right now because it’s still snowing here in May.
Thanks! My Costco membership expired (and there’s no point in renewing in the midst of the pandemic), but I wouldn’t have hesitated to buy them from here.
Amazon had limited on their grow lights, and for whatever reason they now jacked up the price to $84.
The Feit are lighter and convenient – as mentioned I have (2) 2′ 2-tube lights, but the GE are far brighter, and the GE’s whiter-appearing light and reflector side shrouds makes a big difference in ambient disturbances.
One of my GEs has failed already, and another started making a high pitched whine.
Very nice article Stuart. I’m more on the ‘sow outdoors and hope it all works’ method, but seeing what you have going on here I may consider jumpstarting production and getting things indoors. Add it to the covid-things-to-do list.
Honestly… I’ve avoided planting vegetables for a long time now. When I was a kid, we lived on a farm, and got permission from our landlord to use some of the burned out corn field for a vegetable garden. Why? Entertainment Value mostly, but fresh ingredients for salads and the like helped. But I learned a VERY difficult lesson with that experiment. I need to stay away from gardens.
You see… For reasons we cannot fathom, no matter how we examine everyone’s recollection of the garden, I have an entirely unnatural gift for growing plants. Our corn grew 8 feet over a single season, and blocked the light to the rest of the garden, our carrots grew to be a pound each, our beets died in the shadow of the corn, and for some miraculous reason, we planted Yellow Wax Beans on the far row of the garden that yielded between 12 and 35 pounds of wax beans near daily, for an entire season. For a time, the first thing I did after school was grab a large apple basket, and pick all the ripe yellow beans from that single, 20 foot long, row. And every day, for 12 weeks, I would need to take more trips to bring back more. They kept sprouting, out of control, all season. Not only was the corn field dead as a doornail, all we did was add water irrigation from a hose, to soak the soil. Admittedly, the barn’s manure pile was about 100 feet away, and potentially could have leaked nutrients down the hose, which ran by it to get the water spicket. But still… We learned that I should never touch seeds or plants, because I appear to have some sort of unnatural plant growing ability we can’t explain. Both my parents, and my siblings, would touch plants, and they’d die. I’m the only one with this “Green Thumb” problem.
Hell, “Green Thumb” doesn’t even describe it. The way we were pulling down wax beans, at the rate we were, it’s not natural at all. That every row planted by my siblings died almost immediately, is not natural. That the corn seeds we bought were described to reach approximately 6 feet in their first season, but would gain height over time, the longer we left them grow every year… Only to have them shoot all the way up to 8 feet the first season… It’s not natural, and it’s not RIGHT either. We didn’t plan that garden for the corn to be 8 feet, it killed the light for the row directly next to it, which was my Brother’s Beets, and the row next to that was my Sister’s Peppers. I planted the Corn, the Carrots, and the Wax Beans. What happened in that garden was a total freak of nature, and shouldn’t have happened at all.
But, I can say this much… I have been semi-addicted to golden wax beans ever since. If you can find a place in your garden for THOSE… they make spectacular, healthy snacks. Just don’t let a freak like me near them… You’ll have to build a room onto your house to act as a storage silo. No matter how fast they got picked, they ripened and regrew faster every day, until the growing season resulted in them all dropping to the ground at the end. They ripened to the point where the plant decided it was time the beans went to seed. The end of the growing season had a yield of… if I’m remembering correctly… 50 pounds of beans the day we woke up to them having dropped off the plants? Yeah… There’s a “Green Thumb” and then there’s “Stay away, lest he bring forth a plant army.”
To this day, I have never touched a plant like that. I have, occasionally, seen a damaged White Trillium (Provincial Flower of Ontario, Illegal to damage or take away from its growth spot.) and lifted its blossom up toward light a bit, but for the most part, I see plants and stay away. All this talk of seed potting soil just makes me want to build a hydroponics greenhouse, keep a composter connected to the water supply for that greenhouse, and adopt a family of Bats to get their Guano for addition to the Compost. I think, under those controlled conditions, I could safely grow a NATURAL amount of vegetables, legumes, and tomatoes. Keeps ME as far away from direct intervention as possible.
I still have nightmares about having to bring in THAT many beans every day. At least the CORN didn’t grow new ears once you picked one… And the Carrots wouldn’t re-sprout in the same spot… But the BEANS? They’d regrow in the same stem spot you picked from inside a week. And picking the ones off the top that were ripe, gave light for growth for the several layers below them to grow in next… the more you picked, the more ripened… And there was still a barbed wire fence to climb over with each load… Nightmares… I’m telling you, it was a horrible idea to have me plant things. Delicious, yes. SMART, NO.
Always used Miracle-Gro as it’s typically available everywhere
…buy as many as you can! Usually only a couple left on the shelf. Big box stores stopped selling bags of coconut coir, so you can only find these blocks nowadays. Anyone that produces mushrooms will be buying massive amount of coconut coir, it really flies off the shelves.
Half the price for more seed starting mix. If you want to get serious, buy a bag of vermiculite, perlite, and worm castings. Mix ingredients depending on the seed, lighter seed mix for tiny seeds planted at 1/4″ depth or less, use the coir and vermiculite. For beefier seeds, like squash, watermelon, or sunflower or anything planted at 1/2″ depth or greater, mix coir, vermiculite, perlite, and worm castings.
I always use a 2″ plastic pot to start, and transplant everything once to a 4-6″ plastic pot.
Main advantage of coconut coir as a medium is the lack of disease. Many bacteria and fungi are unable to grow in coir. No need to pasteurize it, higher germination rates with lower rates of damping off (common fungal disease).
Stuart, Please do not let the anyone complaining on how you did this trial. I am a mechanical engineer and well versed in scientific methods. I think what you did is quite adequate for this application.
I made up my own soiless mix this year with peat moss and pearlite. My mix was 3/4 peat and 1/4 pearlite. I found the peat moss held too much water and kept seeds from germinating well.
There seems to be very little written on how much moisture is appropriate. Is it better to be too moist, or too dry.
I would like to have seen more on how deep you planted your seeds and what fertilizer concentration you were using and the type of fertilizer.
I will redo my mix again but go about 1/3 peat, 1/3 vermiculite, 1/3 pearlite, and add some worm castings.
Thank you for sharing your experience. Congratulations on trying this too. Do not let the complainers bother you.
Some of my initial seeding efforts resulted in a wet soppy mess, but the coir and peat moss dried relatively quickly. Germination rates were very good and improved further once I moistened the seed starting mixes a little more carefully and with less water.
The only difficulties I had with germination involved “Homemade Pickles” cucumber seeds, which greatly lagged behind germination rates for other cucumber varieties I seeded. I had to reseed 2/3 of those attempts. Each attempt saw 2 seeds, and so the two failures were actually 4 failed seeds. With all other varieties seeing 2 for 2 seed germinations every time, perhaps that particular variety was more susceptible to moisture, or the seeds were old or otherwise compromised.
I tended to plant a little deeper than recommended on seed packets (I also saved such info from the seed sellers’ websites to a spreadsheet), not by intent but because it was too easy to do so. I deliberately tried sowing hot pepper seeds shallower, and that resulted in many “helmet heads” which resulted in leaves being stuck in the seeds or hampered and requiring intervention.
I used a heat pad, which resulted in a lot of condensation in the plastic humidity dome I used, and this seemed to dry the surface to the extent where it was “just moist enough.” I dumped the liberated water every other day or so. I bottom-watered once it looked like I needed a little more moisture, but generally the seedlings didn’t need it due to the nearly enclosed environment.
White fuzzy mold on the Gardener’s mix made it clear when there was too much water, and I vented the chamber and dumped condensate to help reduce the water a bit.
None of the mixes dried out, although the Gardener’s mix compacted a bit more than the others, and it doesn’t look like I water-rotted too many of the seedlings. Judging whether there’s too much or too little moisture is tough, as there seems to have been a wide range of acceptability. I definitely went the “too much water” route at first, but not to the point where germination failed.
For me, the biggest concern was in trying to find the best heat pad temperature. I moved everything from the window sill since temperatures varied too great due to it being a little drafty.
I’ve read that a 1/3 peat, 1/3 vermiculite, 1/3 perlite ratio would be good for container planting, but I’m not certain it would be ideal for seed germination, at least perhaps not in smaller starter cells.
After the initial process of moistening the seedling mix, I bottom-watered and the mix only soaked up as much water as it could hold.
I decided to pack up my lights. I’ll restart with some narrower experimentation in March when it’s time to seed for the 2021 season. From all of this, I learned that the nutrient level is critical for the seedling growth, and I’ll be going with premium/fine worm castings, perhaps comparing that against the Gardener’s organic mix and its built-in compost.
I used a dry powder seedling mix, but knowing what I do now, I’d likely just stick with the FoxFarms dilutable Grow Big fertilizer next year, or the other brand I ordered when I started buying supplies not knowing what would ship on time. They give a ratio for further diluting for seedlings. But really, I think that worm castings will be fine, and added supplements will only be needed beyond the first maybe 2 pairs or true leaves.
The issue I ran into here was that growth was greatly stifled beyond the cotyledon leaves, with most mixes not offering much in the form nutrients or organic matter. The Gardener’s mix resulted in slower germination, presumably because it’s a denser mix with lots of junk in it, but it provided consistent nourishment.
With 3/4 peat and 1/4 perlite, were you top-watering or from the bottom? Aside from the issues with “homemade pickles” cucumber seeds, my germination efforts were largely trouble-free. I could probably optimize things a little here or there, and also keep in mind that my germination efforts were focused on hot peppers, cucumbers, basil, and some flowers. Carrots I sowed outside, and with worm castings proving to be much better than mushroom compost.
I might try my own seedling mix next year, but I can’t imagine the results being any better than I experienced this year, especially now knowing how sensitive the initial growth is to the presence of organic matter and nutrients being available.
I’ve had the best results with Black Gold Seedling Mix and would recommend it.
Our Favorite Germination Trays
Your average germination tray is pretty ubiquitous, and cheap. And yes, you can get ones that are more durable or maybe a different color, they are basically all the same.
Except for the self watering ones.
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I hate taking care of things. Usually I’m out the door by 6am, so remembering to pop in and deal with plants is low on my list. The problem with germination as well as keeping your seedlings going is that you need to keep them well watered or they don’t pop, or die. This is where the self-watering trays come into play.
I’ve seen two easily available self-watering trays. Burpee makes a nice one. But it looks like the media is a bit of a pain to replenish. So I prefer Jiffy’s Self Watering Greenhouse.
Why it’s great
The germination tray works by using a felt pad as a wick to continually keep the peat pucks watered. This means I can pop 10 days of water in this thing, not be particularly religious about checking in, and come back to seedlings that are ready for their first nursery pots.
The pucks are cheap and easy to get. While this tray does come with a plastic insert to keep the pucks in place, they are completely unnecessary. You can use any sized pucks, or spread out the plants a bit if you need to (like for cloning).
Finally, these are amazing for stubborn seeds, like super-hot chilies. Since those plants can easily take 3-5 weeks to germinate, these trays greatly increase the likelihood you won’t screw it up.
Why it’s not great
Jiffy didn’t really build a whole lot of anything into this product… some would call them… flimsy. Don’t try moving this with water in it, or if you do, put it on a sheet pan. Without additional support, it won’t work so well. As you can also guess, they respond poorly to being mishandled.
How to make your own self-watering germination tray
Time needed: 30 minutes.
Gather your materials
b. a thin but relatively stiff sheet of plastic
c. some of those 2Oz condiment cups
d. a normal 10×20 nursery tray with humidity dome
e. a hot glue gun
f. some peat pucks
Cut the plastic sheet to fit inside the nursery tray with about 1 inch on all sides.
Cut the felt to drape over about 2 inches on all sides, then cut the corners out
Hot glue 9 condiment cups on the bottom of the plastic sheet. Poke holes in the cups so they don’t trap air in them and float
Make sure the felt is touching the bottom of the tray on all sides so it wicks up water
Pour water over the top until the felt is soaked and the water is almost to the height of the table
Put your pucks on the table and they will hydrate over the course of an hour. You can speed it up by adding additional water right on them
Once you’re done with the grow, you can machine wash the felt, and clean the tray like you normally would