As mentioned in last week’s post, I will be starting a small container veggie garden this year. Some of you are experts at this, others beginners like myself, and so I thought it would be interesting for me to show you my progress so far.
My plans call for starting some plants indoors for 3-8 weeks, with hot peppers requiring the longest grow period.
I had a late start due to seed company fulfillment delays, but it is what it is.
With some plants requiring a much lengthier start indoors, I saw an opportunity to learn a bit via trial and error before it’s time to start my cucumber plants, which will be quite soon now.
I have done extensive research online, but there’s no substitute for trial and error.
There are plenty of “recipes” for creating your own starter mix, but 1) I don’t need large volumes of seed-starting mix, 2) I couldn’t settle on any single recipe idea as being right for me, and 3) due to the COVID-19 situation, it’s not exactly a good time to visit different home centers and garden centers to amass the needed supplies and ingredients.
So, I ordered some seed starting mixes online, based on what was available to ship. I started with two bags of mix from one supplier I ordered from in mid-March, realized I needed more, and then worked to find seed starting mix from brands I recognized, and from retailers that charged fair shipping.
My first batch of seeds arrived the first week in April. I sowed basil, marigolds, jalapeno peppers, and habanero peppers on April 4th.
Shown above are the sprouted basil seedlings after 4 days.
I planted a second batch of jalapeno and habanero peppers on April 8th when my second batch of seeds came in, and vanilla marigolds as well.
Above, the mix on the left is Burpee eco-friendly organic seed starting mix, and on the right is Gardener’s organic seed starting mix.
The Gardener’s mix is terrible to work with. It has some wood chips, occasional long twigs, even some stones. Their website says it contains Bio-Blended Compost (composted manures and plant materials), sphagnum peat moss, perlite, mineral and nutrient amendments.
I didn’t notice the composted manures and plant materials part before ordering and using it. Usually plant materials or forest matter as some brands describe similar components, is chunky.
I also have Gardener’s non-organic mix on order. It’s less expensive and should be finer as it lacks composted plant matter: Canadian sphagnum peat moss, vermiculite, limestone, wetting agent, mycorrhizae (Glomus intraradices).
The Burpee mix is made from 95% coconut fiber, perlite, and fertilizer.
Looking now at the bag, it says to add fertilizer after 2 weeks of growth.
I do have some water-soluble seedling fertilizer, and I bought worm castings which I planned to mix into the potting-up transplant mix.
But oh boy, I should have added fertilizer earlier on.
In my research, I kept seeing the following repeated: “seedlings don’t need fertilizer.” I’d read and watch that seedlings didn’t need to be fertilized until transplanted, or until “x-number of true leaf pairs” appeared.
Well… thanks to these early experiments, I can see that some seedling mixes aren’t as nutrient-rich as others.
Yes, I know that seedling mix is largely lifeless, lacking the nutrients found in potting mix or garden soil. But seeing the difference is very eye-opening.
Shown here again are the basil seedlings after 4 days. The germination rate for seeds in the Burpee mix (left) is a lot greater than those in the denser and coarser Gardener’s mix (right). Based on this, I told myself that the Burpee mix was better, and I tried my best to source other mixes like it.
My cucumbers will be started in larger 4″ pots, and so I’ll need a bit more mix even. Over the course of the following week, I also ordered Jiffy and Espoma seed starting mixes.
One week later, things were different. I started seeing the differences sooner, but the images aren’t quite as presentable. After a couple of days I noticed that the basil seedlings in the Gardener’s mix were a little ahead in starting their first pair or true leaves.
Here, at the 11 day mark, you can see that the basil seedlings in Gardener’s mix (left) are much greener and larger than those in the Burpee mix.
If you scroll back up to see the Day 4 example, the seedlings in the Burpee’s mix are a little ahead of those in the Gardener’s mix, but this is certainly not the case by Day 11.
The Burpee mix is said to have some fertilizer mixed in, but clearly it’s not as much or as potent as the composted manures and plant materials in the Gardener’s mix.
Here we are, at 14 days. The basil seedlings in the Gardener’s mix are doing great, with large true leaves, and you can see the second pair starting to form in at least one of the seedlings.
On the left, the basil seedlings in the Burpee mix, they are basically stunted.
I thought at first that their shade of yellow-green was due to overwatering, but no, it seems that a lack of nutrients is the cause here.
I’m probably going to have to thin back the grown in the Gardener’s mix and add liquid fertilizer to the seedlings in the Burpee mix.
There’s a ground-side view of the same basil seedlings.
Shown here are jalapeno seedlings after 11 days. There’s greater growth in the Gardener’s mix (left) than in the Burpee mix (right).
I should point out that germination appeared to have been more difficult in the Gardener’s mix, but that seems unimportant given the seedlings’ stronger growth after sprouting.
My first batch of hot pepper seedlings aren’t as populous as the second batch. This could be due to the age or quality of the seeds, as I used different suppliers, or because I was too heavy on the water when moistening the seed starting mix prior to use.
Both the Gardener’s and Burpee mixes were somewhat hydrated out of the bag, requiring only some water to prep for seed sowing. This is important to note because the later mixes I purchased, Jiffy and Espoma branded, are dryer and a lot fluffier, requiring more work and difficulty to moisten, and because a quart of wetter mix gives you more than a less dense quart of bone-dry mix.
Here are the vanilla marigolds after 11 days. Gardener’s organic steed starting mix is on the left, and Burpee’s is on the right.
I did add some liquid seedling fertilizer to one cell in the Burpee’s mix – 4 mL of the as-directed dilution ratio. I’ll be adding more, probably on a once-a-week basis to start, keeping one or two seedlings untreated for comparison purposes. Or, maybe I should dilute it further and apply twice a week. So far, that one application doesn’t seem to have made any difference.
What I’m seeing here and with the basil seedlings is that they thrive with the added nutrients.
I started my last batch of hot pepper seedlings last night a few hours after the packet arrived, and hope to compare the growth nature of all 4 brands of seedling mix I’ve been trying. I have more experiments to try, but I think it’s clear – seedlings definitely need nutrients, and sooner than others and even the brands themselves recommend.
There’s a limit as to what can be added to seedlings started indoors. I have finer worm castings that I could try mixing into the seed starting mix, or I can see how well the water-soluble fertilizer works.
I’m leaning towards assuming that the worm castings, or other in-mix fertilizer, will work better than water-soluble applications.
Or, I can stick with the Gardener’s organic mix in the future, but it’s not without its problems. I had to replace some wood label markers due to mold growth, and the wood bits in the mix seemed prone to grow white fuzzy mold.
To get things started, I have a heat mat and a humidity dome, with the 6-cell seed trays removed from both once an acceptable number of seeds have sprouted. I have also been using growing lights – one kind over the humidity domes, and another for the seedlings as shown here.
Here’s another angle showing the vanilla marigolds. It’s crazy how much of a difference the seed starting mix makes.
Right now, I’m on a race to get the hot pepper seeds ready for transplanting outside in 4-6 weeks. The ones I just planted yesterday won’t get to enjoy the full 8 weeks of recommended growth before heading outside.
I’m going to have to figure out a fertilizer regiment, and fast.
Here are the 4 trays that I started yesterday, all with sugar rush peach hot pepper seeds. I used the whole packet, since there won’t be time to start any more plants later than now. I can always order more seeds for next year, and I probably will if things work out well.
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
- Burpee organic seed starting mix
- 95% coconut fiber, perlite, fertilizer (0.06 – 0.03 – 0.03)
- Jiffy organic seed starting mix
- 60-70% sphagnum peat moss, vermiculite, coir pith, and lime for pH adjuster
- Espoma organic seed starting mix
- 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
As mentiomed, the Jiffy and Espoma mixes were very dry out of the bag, and I have found them to be more difficult to work with. With the Gardener’s and Burpee mixes, I can add a little for them to be moist, or a lot for them to be damper. My first sowings were a little too damp, and with the second batch I was more conservative, working with less water.
With the Jiffy and Espoma mixes, I can’t get as good a consistency – even if I mix everything well and add just enough water to hydrate the dry mix, it ends up wet and spongy. This will likely require some “trial and error” for me to get right, although that depends on how germination and growth progresses.
Another bucket of carrot seeds are going outside today, but I’m not experimenting much there – for now.
I’ve been tempted to sacrifice a plant from each tray to see if there’s a difference in root growth. My initial thoughts about maybe the basil being overwatered due to the type of mix have been invalidated. The mix on the left simply has more nutrients to facilitate growth, via “Bio-Blended Compost,” while on the right, the “fertilizer” obviously hasn’t done much.
Seed Starting Mixes
Note: A lot of these supplies are no longer available via Amazon or other retailers, but at least the links will show you what the packaging looks like.
Other Seed-Starting Supplies
- 1020 trays, humidity dome, 6-cell trays: via Bootstrap Farmer, via Bootstrap Farmer on Amazon
- Feit LED grow light
- GE LED grow light – I like this one better
- TP-Link Kasa Smart Plug (for grow light timer functionality)
- Rubbermaid utility tray (so that I don’t make too much of a mess in the kitchen when sowing seeds)
- Hydrofarm seedling heat mat
- Hydrofarm Jump Start heat mat thermostat
- GE power strip
- Wire shelving – I use a larger rack, but am planning for a smaller one
I ordered all of the seed-starting supplies from Amazon, except the Bootstrap Farmer supplies, which I ordered from their website directly.
- Eden Brothers
- Fastest shipping, missing one seed packet, fast customer service but more than 2-week wait for the missing item
- Territorial Seed
- Second fastest shipping on first order, better seed packet info, temporarily closed to new orders, transplants to come later
- Reasonably fast shipping, transplants to come later
- Park Seed
- 4 weeks and nothing received yet
- Baker Creek/Rare Seeds
- Fast shipping (although they only reopened recently)
Seed suppliers are absolutely inundated with orders, partly because this is their busiest time of year, but also because of the COVID-19 pandemic, social distancing for workers’ safety, and much-heightened customer demand.
Different suppliers carry different varieties, and so I had to split my orders among different suppliers. Once I realized I might not be able to receive and start plants by seed on top, and not knowing whether I’d be able top shop at the local garden center or what they’ve have, I also ordered live plants for transplanting from Territorial Seed and Burpee.
We have one room of the basement devoted to seedlings . We have 4 six foot long narrow benches with an array of older style – 8 foot long fluorescent fixtures hung on chains. When I built all of this – the conventional wisdom was that the effective light from a fluorescent tube fell off near he ends – so an 8 foot tube gave more than double the effective light of a 4 foot tube. I guess I could have done some testing with a light meter – but now I have fixtures with the old-style 75 watt single pin bulbs. We have one smaller bench at the end that has 2 – 4 foot shop lights – that I’ve fitted with tubes that have a better color temperature for plant growing. My wife uses this bench with Hydrofarm warming mats under the seedlings. We control the lights via Tork Timers. If I had to do it over – I’d probably go with the LED lighting you used – but 40 years ago ???
My wife also uses a gizmo to create soil cubes for some seedlings:
I have one of those soil blockers from Johnny’s as well. Great tool! We mix up a decent potting/ seed starting soil with water to make the blocks. The tool leaves a small indent for the seed, which we cover with vermiculite. The blocks make transplanting to bigger containers or the ground easy.
I have also seen those soil blockers, and added it to my “maybe next year” wishlist.
The thing is, some of my seedlings needed to leave the germination conditions at different times, and it was easier to move a 6-cell flat that individual blocks, or try to improvise mini trays within a larger tray.
I’m also bottom-watering, and didn’t know how well those soil blocks would hold together.
Plus, while some of my seedlings will only spend a few weeks indoors, the longer ones will be here for up to 8 weeks.
In other words, it looks like a good product, but I worried too much about how well I’d get it to work for me this year, and so I decided to go with seed starting cells.
I also ordered small and medium-sized coir pots, but I don’t know if I’ll use them this year. In theory they help keep roots intact between germination and transplanting, which is important for some plants such as cucumbers which don’t respond well to any root disturbances.
Makes sense, I can see why the soil blockers wouldn’t always be the best choice. I bottom water my blocks, but you do lose some of the soil if you leave them in water too long. I have my blocks in leftover trays, I assume from buying a flat of plants at some point, which helps keep them together. I can get about 65 of the size blocks I have per flat. I TRY to keep plants with similar germination rates together, but that doesn’t always happen.
I’ve never personally used the coir pots, but I know someone that swears by them. She starts with blocks in flats and then transplants to the coir pots.
Nice progress Stuart. Wife and I have been following your seed starting adventure all along, and facing similar issues regarding finding supplies, seeds, etc during these crazy times. We’ll be building some cedar outdoor planters as well, provided we can find the lumber.
What fertilizer did you use for your seedlings? We’re currently growing from seed indoors using that same GE light.
Been reading your blog for years and have found tons of great tools and insights thanks to you. Keep up the great work man!
Thanks, I appreciate it!
For the most part, nothing has been fertilized so far, except for (1) marigold cell. The fuller and much better-looking seedlings are simply sown in the Gardener’s organic seed-starting mix, which seems to have tremendously more nutrients than the Burpee mix and other basic mixes I’ve also started experimenting with. Basically, the Gardener’s organic mix has a compost mixed into it, the Burpee some unspecified fertilizer of apparently low quantities. Or it could be that the Burpee nutrients are hard for the seedlings to access.
Once I realized that some of the seeds I had intended to buy were sold out and suppliers were being hit with demand, I panicked a little bit and bought everything I thought I’d need from Gardener’s Supply.
This is the seedling fertilizer I thought I’d try: https://www.gardeners.com/buy/seedling-fertilizer/11727.html . I believe I used a 1/4 teaspoon into ~11 oz of water, or similar – I followed the dilution instructions. After this post, I added 4 mL of the solution to each cell. I’ll bottom-water everything tomorrow.
There is a lot of info out there, and I had to pick and choose what I’d have time to research and what I needed to source while I could.
My local garden center is open, and I might browse there a little more in the future, but for the time being I figured the seedling fertilizer would be a good “I don’t have to think about it” start.
I also ordered general purpose slow-release fertilizer pellets, tomato pellets that came with a self-watering pot package, and later also Espoma tomato pellets in case it’s needed. Tomato and pepper nutrient needs are similar, and I figured I could use general purpose fertilizer on the cucumbers and other plants or shared spaces.
I also ordered premium earthworm castings, which I don’t seem to be able to source locally (via Amazon). They have a “standard” variety, but the premium is finer-sifted, which makes it better suited for use indoors as well as out. I might try that with some of the cucumber starts to see if it makes a difference.
I also ordered different liquid fertilizer from territorial seed, but haven’t used it yet.
I wouldn’t be trying so many things for personal use; once I switched to thinking I’d deepen my exploration for editorial purposes, I allowed myself to spend a little more than otherwise.
Container-wise, I still haven’t found the time to finalize my cedar planter plans. I have the two Greene’s, but am also trying grow bags, 3.5 and 5 gallon buckets this year, plus self-watering container from Gardener’s. I couldn’t commit to any singular plan, and my “let’s experiment!” mindset took over.
If you can’t source cedar and all fails, food-safe buckets ship very quickly from Uline, although shipping rates went up between my first order a few weeks ago and my order this week.
The cedar deck boards from Lowe’s seem to be decent, and Gardener’s raised garden cedar boards seem to be premium quality, and although they’re pricey, the final cost-per-foot seems reasonable or at least competitive once shipping/delivery is factored in.
Wow Stuart, thanks for the informative reply!
Crazy how much of a difference that soil made. We did get a seed starting soil, can’t remember the name at the moment, but our results are moving along nicely, albeit a little slower. Looking into some fish and kelp 2-2-2 fertilizer as a boost.
Have been looking at those grow bags too, seem like a great concept and have been toying with the idea of building a decorative cedar paneled box to encase the bag.
Last year we grew oregano in a window box from a small six inch pot. It was prolific and went into hibernation during the winter and is now coming back with a fury. Wasn’t expecting that but I’ll take it.
I’ll check out those deck boards. Need to reread your post on all that from a while back, I know there was a lot of info there.
Interesting to see the difference in growth. We got some of those mini plastic greenhouse starter kits along with soil from Walmart and had good success with a variety of Veggies.
It’s interesting how much this Coronavirus changes your thought process. I’ve been to a store twice this month. Once to Home Depot for building supplies and once to Walmart for groceries. We’ve been stretching the grocery trips out to weeks and I think we’ll be able to make it three before the next one. Our local store was limiting to one gallon of milk and one loaf of bread in March, but is now only restricting TP and some cleaning supplies.
Our garden space is slowly taking shape. I’ll need to do one more trip to Home Depot to get it finished, and then have the fence extended.
I’ve had good luck with starters in both “Rapid Rooter” coconut plugs and rockwool plugs soaked in a quarter to half strength nutrient solution. I know you are going to be using soil, but the seedling portion of the endeavor isn’t much different, and you can easily flip from hydroponic nutrients to soil nutrients whenever you want. Using a hydroponic type setup for the seedlings comes with it’s own issues, but it would help to prevent some of the issues you’ve had – mainly sourcing consistent potting soil and having issues with nutrient levels.
I’ve actually been using about 20% of my seedlings this year… The other 80% have been going to family and friends as gifts. The seedlings that I’ve germinated in the coco plugs seem to be doing great so far for others who are dropping them in small indoor pots or the ground outside. Haven’t had any of my rockwool seedlings transplanted to soil yet, so the jury is out there, but I am sure by the time they are ready their roots will be expanded right to the edge of the little cube anyhow.
Good call on the bottom watering and the grow lights! They help a ton.
I’ve found a lot more success since I made a ‘two stage’ setup for my seedlings. I have “stage 1” with the plastic cover, a bit of water in the bottom, and a temp controlled heat mat. “Stage 2” is in a flood pan with the grow lights. Both stages have a ~2’x1′ seedling tray with a ‘grid’ insert to hold 6×13 plugs, allowing easy moving between the two without having to label each seedling. As soon as I see any activity for a specific seed, I move that ‘plug’ into stage 2.
As someone that 30 years ago managed a mostly bedding plant greenhouse, I have stuck with Jiffy Mix for seed starting soil. Not sure what difference the organic designation has to it now, as that is all I have been able to source for some time. Wetting it was always an issue, but I never ventured to try anything else.
For potting soil, I have also always stuck with Pro-Mix BX (https://www.pthorticulture.com/en/products/pro-mix-bx/#tab:product-specification) since it was the mainstay in the greenhouse. Hard to find, but none of that wood product stuff added to it. And it includes a wetting agent, which greatly helps. I get a 3.8 cu ft bale of it every season. The company has various soil mixes available that might fit needs better, but it works for me.
As an aside, a nitpick my old high school horticulture instructor instilled in me is to cringe at soil being referred to as dirt.
My horticulture professor repeated this so often I can still hear him 45 years later, “Dirt is what’s behind your ears. This is soil.”
There’s a book called “Start with the Soil.” Highly recommended by the folks that teach organic gardening classes locally. It will give you a new appreciation for soil.