how to start seed indoors

NO GREENHOUSE, a tiny house, and various other obstacles notwithstanding, I’m madly coaxing along one crop after another of seedlings over here. Want a little tour of how to start seed indoors (well, at least Margaret’s improvised method, that includes some outdoor steps, too)?

My house is too small for make room for grow-light stands and seedling flats, and you wouldn’t want to even think of climbing down the ladder into the cellar here a couple of times a day to care for seeds. No matter:

I improvise. My “potting bench” (above) is the backyard on a fair day, where it matters not whether potting soil goes astray. I simply bring all my supplies out, sit on a footstool and make my mess.

Important: I lightly pre-moisten the germinating mix right in the bag a day or two before, massaging it and turning it a couple of times to let the water I’ve added absorb evenly.

If I’m re-using nursery pots, flats or cellpacks, I wash them first in soapy hot water or a 1:10 bleach:water solution (above, cellpacks soaking).

Once the flats are filled with the barely damp mix and the seeds are sown, I let the sown flats, fiber pots or cellpacks wick up more moisture from below, setting them briefly in a dishpan or roasting pan of water. Seeds want to be very moist to germinate.

The electric germination mats and lights are waiting in a nearby shed that has just the tiniest amount of electric baseboard heat. The heat mat set-up (below) is simply a partial piece of plywood balanced on top of a storage bin, set underneath a table. On top of the table: a light stand, one of two I own (the smaller one is two photos down below). I keep the shed in the low-60s F at this time of year. Primitive at every step, perhaps, but effective.

I put the well-watered seedling containers in waterproof flats, covered with plastic wrap or plastic bags or lids, and set them on heat mats just until the seeds begin to germinate (important: no bottom heat after the seeds sprout!). As soon as they show, I remove the plastic, and move them quickly to a spot under my T-5 grow-light hoods set on timers for 12 hours of light a day, and adjustable in height to shift as the seedlings grow. I keep the lights very close to the young plants–just a couple of inches away at most.

I water more sparingly once they are up and growing, letting the germinating medium surface go just dry to the touch between waterings. I don’t feed until plants have true leaves, and when I do feed, it’s with a dilute solution of fish and seaweed emulsion.

Once the seedlings have had true leaves for a week or so (and assuming the weather is not blustery) I carry them outside daily to enjoy sunshine and air all day. I set them in a spot near the house that’s bright but somewhat protected, especially at first; my bright back porch is good. Above, a few cool-season things on their daily outing.

Again: I do this only on fair days, but it gives the young plants more light than they’d get artificially, and also creates a stronger, stouter seedling that’s essentially being hardened off along the way. (A Cornell plant physiologist explains here how much stronger outdoor light is from even the brightest artificial bulbs.)

If you can’t carry things outside daily all along, be sure to harden off seedlings for a week or longer before transplant time. Put them outside by day, for a partial day at first, gradually increasing their exposure. To minimize shock, I like to transplant on an overcast day when it isn’t too windy, or best of all: just before a gentle rain arrives.

more help with seedlings

• When to sow what (a calculator tool)
• Why seedlings stretch and what to do to prevent it
• Tomatoes from seeds: steps for success
• Melon-growing 101
• Seed-starting FAQ page