The lone voice of horticultural reason

Starting Plants from Seed

3-15-01– In what month does the gardening season truly begin across this great, frozen berg we call home? March, of course, when all good northern gardeners start plants indoors from seed.

Anyone interested in gardening should try it. Starting plants from seed is primal, basic, Biblical stuff; magical, if you ask me. You plant this hard, tiny nit of a thing into a sterile medium indoors and three months later it’s four-feet tall and feeding bees in your garden. Starting plants from seed winds up and smacks my soul at the core. I wave to my great-great grandfather Anders in Norway every time I plant seeds. He halts his horse-drawn plough, mops his brow with a clean, ironed handkerchief, nods and waves back.

Some hesitate to try starting plants indoors from seed out of uncertainty, some try it and quit out of failure, and some try it and get so hog-wild addicted as they slip deeper into the endless minutia, their spouses leave and it’s days before the note is read. None of these scenarios need apply, if you keep a simple task simple.

First, understand there are some basic laws in effect. Seeds germinated in styrofoam cups on top of the refrigerator, then moved to the sill of a sunny picture window, will always result in thin, leggy, yellowing plants you throw into the kitchen wastebasket on May 15th. There are no exceptions to this law.

To successfully grow plants from seed indoors you must find an out-of-the-way place to set up a proper growing table. You need to hang lights above this table, so a ceiling that will succumb to a bit of carpentry is essential. The growing process can get a little messy, so a tile or concrete floor is handy. If that floor is cool to the touch, that’s a definite bonus. Add them all up, and you’re in the basement.

My basement growing table is nothing more than a four-foot square sheet of half-inch plywood raised up forty-two inches on two-by-four legs. Sawhorses are too low; you need to be able to work at the table without bending over and straining your back, particularly on those blessed Saturdays when your spouse is off on a daylong jaunt, and you can finally get in a solid four-hour shift tending your plants.

Around mid-March I start my annual bedding plants, and a half-dozen or so perennial varieties with which I’ve chosen to goof around, all within the confines of my four-by-four table. That’s right around 250 plants. Already, I know what you’re thinking: What if that’s not enough? My advice to first-timers is: moderation at the start. Ease into it. Get a few successful years under your belt, then take over the ping-pong table. Raise it up first.

The biggest necessity for growing plants indoors from seed is artificial light. There’s no sense in devoting any time to the project without it. Plants from seed grown by a window become impossibly sad specimens, even in the sunniest spot in your house. The sun’s rays are simply too weak and the days too short for young plants to receive their gigantic daily requirement of energy.

At the hardware store you will find inexpensive shop lights for sale. Each light is four-feet long, constructed of flimsy metal, and houses two fluorescent bulbs. Pick up two eye hooks and two small pulleys for each shop light you buy, and some 1/4-inch nylon rope. The plain fluorescent bulbs that come in the box work fine, but be sure they’re kept clean, particularly after you fire them up the second year. After two years, replace them, because even if they aren’t burned out (they won’t be), they’ve lost much of their punch.

For annual bedding plants and perennials, I buy the white trays that hold 36 plants in two-inch, black plastic “cells.” Sometimes they come with 36 individual, white plastic pots, and those are fine, as long as the set includes a raised, clear plastic lid.

I steadfastly ignore peat pots, peat pellets, ornate mini-greenhouses, and anything with a label featuring the word “instant.” Peat pots are everywhere in the stores, and came about when some garden industry marketing team realized that if they made small pots out of compressed peat moss, they could advertise that at planting time, nothing could be easier than planting the whole pot. The fact that peat pots dry out in your basement the moment you look away, wick moisture from the ground when planted improperly, and hamper fine roots from spreading quickly, never made the press release. Stick with the white plastic tray sets. During the crucial germination and early growing stages, you’re after controllable consistency in regard to moisture levels, and plastic delivers.

Now for the growing medium. Just the other day on the shelves I noted bags of a new potting soil called Flower Seed Starting Mix. Of all the nonsense. What the garden industry desperately tries to market each spring is new products, whether they advance the science or not. What next? Vegetable Starting Mix? Herb Starting Mix? Shade Annual Starting Mix? All that was in the bag was the same old mix this company has sold for years, with a little fertilizer thrown in.

As if the tender, baby hair-like roots of a sprouting pansy or petunia and their cultural needs are in any way different from the roots of a young radish or green pepper plant. I had half a mind to buy a bag of the stuff, sow tomato seeds in it, blast ’em with light, and when they were eight inches tall ship about ten, stout, lush tomato plants to the manufacturer with a note saying, “Explain this.”

Use any mix that lists peat moss (retains moisture), vermiculite and/or perlite (lightens the soil, retains air and moisture) and loam (dirt, for volume). But be sure it’s a high-quality, sterile medium. One year, inexplicably, I settled for a national chain’s private label brand of potting mix, and was rewarded with an unexpected crop of marauding clovers, thistles and fescues germinating in competition with the sown seed.

Here’s an important tip. Don’t fill the two-inch cells with dry potting medium, and then try to add water. Even if you water the bottom of the tray, it can be days before the peat moss and vermiculite in the mix thoroughly absorb the water. Instead, dump the mix from the bag into a five-gallon bucket, until the bucket is half full. Then add tap water (unsoftened) to the bucket. Roll up your sleeves and kneed it all together, whipping it and squeezing it with your hands until moistened. Add a little more water if some of the medium remains dry. I test it by taking a handful and squeezing it, hard. If water gushes out as it would from a heavily soaked sponge, it’s too wet; add a little more medium. If just a little water trickles out and runs down your arm to your armpit, it’s perfect.

Fill the cells in your trays with this pre-moistened potting mix. Tamp it down so there are no gaps or air pockets near the bottom, but don’t compress it too much. Leave about an eighth to a quarter of an inch lip at the top.

Sowing the seed is great fun, and an activity that children and even spouses enjoy. Germination time (the number of days between planting and sprouting), planting depth, and special instructions are given on the seed packet. If you’re new to this, the easiest seeds to start are those listed as needing light and around 70-degree temperatures to germinate.

This includes most annuals. Impatiens are easy, and Coleus never fails. Zinnias are also a snap to grow from seed, the only downside being, of course, that when it comes time to plant in the garden, you’re stuck with zinnias.

Plant two seeds per cell. “Do not cover – needs light to germinate” doesn’t mean you shouldn’t put the plastic cover on the tray, it means don’t bury the seed. I had to think about that one the first time, but then, I think too much. When you’ve filled your tray(s), mist the surface of the soil, then seal the tray with the clear plastic lid. Your trays sit on your growing table below the shop lights that are affixed on each end with nylon rope running through the pulleys fastened with eye hooks into the ceiling. One shop light covers a one-foot by four-foot area of table, meaning you need one light for two full trays, two lights for four trays, etc.

Lower the lights so they hang about half an inch from the top of the plastic tray covers. In your average, cool basement, the heat of the lights will raise the temperature of the soil surface to between 70 and 75 degrees, which is perfect.

Leave the lights on sixteen hours a day. Cheap timers, the ones sold to turn lamps on and off when you’re on vacation, are the only way to go. I have my lights set so they come on at 7:00 am and click off at 11:00 pm, seven days a week.

A little condensation will occur on the inside of the lid, a good sign. I remove the lids for five seconds every couple of days, just to change the air in there, and to be sure the soil is moist, but basically you’re leaving the lids alone and watching for germination.

When the seeds germinate and tiny plants emerge, I leave the lids on for another day or two if more than half the seeds are lagging behind. However, the lids should come off for good no more than three days after first spotting germination.

At this point I raise the lights to four inches above the tiny plants, increase the number of hours of light to eighteen, and add a small fan to the proceedings. A small fan (or heater, set to “fan only”) gently circulating air across the table lowers the risk of damping-off, a fungal disease that causes the seedlings to buckle at ground level, then die. Hook the fan into the jumble of timers, two-way plugs, and extension cords you will have discovered procreating like snakes across your basement floor.

Now, monitoring moisture is key. Your duty is to keep the potting medium damp but not wet. The nice thing about having peat moss in the potting medium is it’s dark brown when moistened, light brown when dry. After germination, start watering with a small amount of all-purpose, 10-10-10, water-soluble fertilizer mixed in, at the ratio you use for houseplants (about a teaspoon per gallon). After a week or two, pluck out the weaker of the two plants from the cells in which both seeds germinated. As the plants grow, maintain the lights at four inches above the tips of the plants

As warm weather approaches, the books say you need to start hardening off your plants. Hardening off means taking the trays outside to a shady spot for half a day three days in a row, then eight hours for four days, then finally leaving them out for good (provided all danger of frost is past).

I did this up and down the basement stairs with over a dozen trays for about the first two years, then said to heck with it. If any plant is going to be in Don’s Army, it’s going to learn that life is tough. In early May, unless frost is eminent, I haul my trays out once and leave them out for good. As long as the soil in my garden has warmed by the time I plant, usually after only a few days of this abrupt hardening off, my plants do fine.

As will yours. I’ve grown beds of impatiens that people have marveled at, stopping to ask me what greenhouse I buy from, because their impatiens never look as good. You’ll begin to experiment, and fall in love with, flowers unavailable from your local nursery.

And sure, add up all the expenses, including your time, and each plant winds up costing you around fifteen bucks. But that’s a small price to pay, to be gardening in March.

Don Engebretson
The Renegade Gardener