GARDEN TIP – Indoor Seed Starting

Melon Man Gene is here to explain his method of starting vegetable seeds indoors. His gardening techniques have appeared in two earlier posts — The Melon Man and Save Them Peels, Ma’am.  Gene has traditional commercial farmers in his lineage. Gene did not follow that path and, like me, he often figures things out by trial and error. He admits to a lot of failures but learns a lot that way and often photographs his failures as reminders. Without further chit-chat, I’m turning it over to Gene:

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SEED STARTING MIX. Avoid compost for seed starting. Compost can hamper germination. Potting soils are more likely to be free of the fungus that causes dampening off. I use a good potting soil, such as Miracle-Gro, rather than a seed starting mix.

Miracle-Gro has a built-in fertilizer giving the seedlings a good start and eliminates the worry of adding fertilizer until later. I’ve found that despite how long the bag claims the fertilizer will last, it doesn’t — possibly due to how I water. As a result, I watch the plants and when the growth seems to lag or the green color fades (this can also happen if the seedlings aren’t getting enough light), I’ll add a liquid, balanced fertilizer to the water the seedlings get.

SEED POT.  Many gardeners start seeds in small peat pellets or seed starter trays planning to “pot up” later. I believe this is a waste of time and resources. I start my seeds in 18 ounce plastic Big Red Cups which allow the plant to grow from seed to the finished seedling.

I use a push pin to poke holes all the way around the side of the cup at the bottom edge. Click one of the three images to see slideshow.

I fill the cup with soil, and then place the cups in a plastic tray that is capable of holding water.

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When adding soil to the cups, I try to make sure there are no soil “lumps” that will cause large air spaces in the growing medium to interfere with wicking.

To start the wicking action, I gently pour water in the cups trying not to compact the soil any more than necessary. The soil at the very top of the cup is often dry. Go down about 1/8th inch to check that the water is wicking properly. You may not have made the side holes in the cup large enough.

After watering all the cups, I pour water in the plastic cup holder tray until I have about an inch of water. I do this at least 24 hours in advance of when I want to plant seeds. After 24 hours, I check to make sure the soil at the top of the cups is just slightly moist. The soil will draw the perfect amount of water up through the cup. If the soil at the top is dry, then it needs to sit longer, or I didn’t pour enough water down through the cup to get the wicking started.

Make sure the water level in the plastic cup holder tray never drops lower than the holes in the cups. If it does, and the cup has gone dry (and the plant isn’t dead), water must be poured IN the cup AND the plastic cup holder tray to insure the wicking action begins again.

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SEED MARKERS. I use large Popsicle sticks for labels. They are easy to write on, cheap enough to be disposable and safe for my soil. As a wood product which easily breaks down in the soil, I don’t have to worry about collecting all of them at the end of the season. Sometimes they break down too fast and introduce organisms into the soil that increase the probability of dampening off. I don’t consider the Popsicle sticks an optimal solution, but I’ve not yet found a better one.

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SEED STARTING BENCH. The seed starting bench in my basement was there when I moved in. Using scraps of lumber already on hand and some PVC piping, I built a sturdy frame to support the shop lamps.

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I use florescent shop lamps with T-12 light bulbs for two reasons: (1) light and (2) cheap. The T-8 light bulbs aren’t as bright and I’m concerned with making sure my plants get enough light. I use the 40 watt bulbs with a color temperature of 4100K. It’s possible that different color temperatures may work better, but my research led me to get something “in the neighborhood” that was inexpensive and readily available at Home Depot. The lamps are around $10 each and the bulbs are about $20 for a box of ten. DO NOT spend money on special “grow lights” or “grow bulbs.” From experience, I can tell you they aren’t worth the extra money. They don’t last as long, don’t produce as much light, and the standard cool light bulb has produced better results.

If the bulbs are used only for starting seeds, consider reusing bulbs from year to year, but keep in mind that florescent lights dim with use.

CHAINS FOR THE LIGHTS. I got custom lengths of chain to go on the lights. The exact length of chain needed depends on the set-up and the height of the seedlings grown. Four feet of chain has been more than enough for my purposes. Raising and lowering the lights is critical to successfully starting seeds.

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Regardless of how the seed starting bench is set-up, smooth rounded surfaces like PVC make it easier to raise and lower the lights where the chains from the lights wrap around the bench. The chain can catch on the edges of wood and become difficult to manage. My set-up is not optimal because I made use of a pre-built frame under the bench. Still, this provides two levels of lights allowing me to maintain two different growing temperatures.

One advantage to being able to adjust the lights with chains is the ability to cluster tall and short seedlings in separate groups. With both ends of the lights adjustable by chain, the lamp can be hung at an angle (see last photo).

GERMINATION – LIGHT. In general, seeds need no light to germinate – they can be started in the dark. The second they pop out of the ground, however, the lighting must be sufficient or the seedlings become long, leggy, ill-formed and prone to breakage/death.

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The goal is to keep the lights as close to the seedlings as possible because the strength of the light will drop off rapidly with distance. However, the closer the seedlings are to the light, the more often they need to be checked. The light bulbs I use are cool enough that they won’t burn the plants but plants left unchecked can grow up around the bulbs requiring removal of the light bulb to extract the seedling.

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Often, a seed can be spotted before it pops out of the soil — a little curve that just barely reaches the surface. A few hours to a day later, that curve will make it far enough that one end has popped out of the soil and the seedling is on its way.

GERMINATION – HEAT.  Heat is needed for starting the sprouting process. Without heat, germination takes longer. Burying the seed too deep also slows germination. I recommend pre-soaking or at least dipping seeds in water before planting (depends on the seed).

Some seeds are VERY picky about their heat – enough so that germination will be very low, or not at all. Tomatoes and peppers, in particular, like temperatures around 85°F. They’ll germinate with less, but it takes longer with lower germination rates. A digital thermometer is useful. I prefer one with indoor and outdoor settings (with a probe for outdoors). I can insert the probe in the Rubbermaid water tray and usually the water temperature is the same as the temperature at the root zone. Plants care more about the temperature of their roots than their leaves. The warmer the root zone, the faster they grow, provided the temps match the preferences of the plant.

Another option is a small heater or seed starter heat mat to temporarily increase the temps under the lights, if needed. It should have a temperature sensor to control how hot it gets.

In my set-up, I use layers of thick black plastic sheeting (from Home Depot’s paint department) to completely cover the upper section of my bench (see bench photo above). Light hitting the black plastic is converted to heat which becomes trapped inside the black plastic cover. Because it’s layered, it’s more effective as air is trapped between the layers for additional insulation. This also captures heat given off by the lights because they are not 100% efficient in converting electricity to light. Heat generated by the lower level lights rises up through the table to provide more heat. With no heating other than the lights themselves, I can often maintain a 20° F temperature difference between the temperature inside and outside the plastic. For instance, if it’s 55°F in my basement, it’s 75°F where the seedlings are. This higher heat makes me prone to sticking my head under the plastic to check on my plants instead of raising the plastic and letting the heat out. There is one drawback to this set-up — the temperature difference causes condensation to form on the plastic and drip to the floor.

AUTOMATION. As much as possible, I automate everything. Seedlings are self-watering via the Rubbermaid plastic tray and lights are on a digital timer (the cheap, mechanical ones work fine, too). It’s important to use long days with the timer – around 16-18 hours of light. Longer days with weaker light help compensate for not having brighter lights. Mine is plugged into an electrical strip and programmed to come on about 6 a.m. and go off about 11 p.m.

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If your seeds are being started in a location where the seedlings get too cold at night (assuming you are not using any natural light), you could turn the lights off during the day and on at night. That way the lights are providing heat during the coldest period of the surrounding environment, and no heat during the warmest period of the surrounding environment.

FERTILIZING. When fertilizer is needed, pour liquid fertilizer directly in the plastic cup holder tray and stir the water in the plastic tray to help disperse the fertilizer. Use less than the recommended amount. Half is probably a good place to start. More fertilizer can be added later, but if too much is used, seedlings may be dead before the mistake can be corrected. One way to leach away nitrogen when too much fertilizer is added, is a complete water change in the plastic cup holder tray, and a good water flushing of the cups themselves.

SEEDLING GROWTH.  As my plants get older and taller, I move them to the lights under my grow bench. This provides room above for starting new seedlings and exposes the mature seedlings to colder air to begin the hardening-off process. The colder air also slows growth to avoid them becoming root bound.

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SEEDLING STRENGTH. If you live in an area prone to high winds, expose your seedlings to wind, preferably from different directions, before planting out. It’s not something that has to be done but it will help towards the end of the seedlings’ indoor growth period. Gentle wind will make the seedlings form stronger stems so that outdoor winds don’t snap the plant tops off. An oscillating fan works best for this.

I hope this encourages you to start your own plants from seeds. You still have time in most of the U.S. If you have further questions, ask Gene and he’ll do his best to answer.

All photos are attributed to Melon Man Gene.

13 thoughts on “GARDEN TIP – Indoor Seed Starting”

  1. Oh, this is fantastic. Thank you Melon Man Gene for the instructions and thank you Linda for posting it. This is just great. Thanks again.

    1. Lynn – I found it very informative, too, because I started my seeds last year (haven’t this year, thus far) and my system just wasn’t working as well as his. I didn’t have my seedling trays sitting in water, I didn’t think about angling the lights for tall/short seedlings, and the list goes on.

  2. I had been wondering whether potting soil was good for seedling starting; now I know. I’m guessing that if it works for vegetables and, presumably, melons, strawberries can be started in the same manner? If I want to have a planter garden, should I continue to grow my plants in potting soils?

    1. Mad Tattah – I would because it is more enriched than regular garden soil. Now MY veggie garden is regular garden soil because I can’t afford to cover 28 x 28 feet of yard with potting soil. I’ve been trying to amend it with compost and leaf mulch and it’s still not great soil.

      1. Your garden soil probably isn’t that bad. Get a soil test. You’ll probably find out it’s much better than you think. For that matter, if you want to test potting soil, you’ll probably find out it’s much worse than you think. Potting soil is good because at least some companies will sterilize it (good for avoiding dampening off issues), and it’s got enough fertilizer in there to get things started. Were it actually good soil, you wouldn’t see them adding fertilizer like that because it would already be in the soil. The only measure of “good” for soil is does it provide the nutrients you need, and does it cause any drainage issues – beyond that, you can use anything for soil – including styrofoam packing peanunts because all it’s doing is holding the plant. Check out hydroponics sometime. No soil required. Any soil though will benefit from healthy amounts of organic matter – a lot of which will routinely go in your trash if you’re not composting or feeding your composters (chickens :P).

    2. The “Yellow Wonder” above are apline strawberries. It works fine. The only thing to beware of with a container garden is that once something goes into the container, it’s very difficult to get out. It’s also (to me, anyway) rather difficult to mulch a container. If your plants will tolerate it, you may want to change the soil in the container every few years – and be extra careful with the fertilizer – and think about anything that may be in the water you’re using to water that might build up and cause issues (like salt).

  3. This is interesting and very useful info. I intend to save it for future use. Mama usually started her seeds but I never paid much attention. She and I always use Peters’ Special for making our liquid fertilizer. Please thank Mr.GreenGene, I mean Melon Man Gene for his great instructions.:)

    1. Now Mr. GreenGene woulda been a good name for him if I hadn’t previously introduced him in an earlier article as Melon Man Gene. Based on some photos I downloaded that he made available to me, he is currently using Bonnie Herb & Vegetable Plant Food which, according to the back label, has 2.92% urea nitrogen. Now, urea to me is pee. I’ve read in old articles of Mother Earth News that we should uh, um, well, you know. Problem is, I don’t have the personal equipment for easy collection and I take certain meds that I don’t want showing up in my veggies.

      1. And it would be WAAAY too strong for the plants. You really don’t want to use very much. If you think you need to, you’re better off using less and doing it more often.

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