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Start with right seeds indoors

| Friday, Feb. 22, 2013, 8:57 p.m.
Seedlings ready to be transplanted into the garden last May.
Jessica Walliser
Seedlings ready to be transplanted into the garden last May. Jessica Walliser

This is the second article in a two-part series about starting your own seeds.

In last week's column, I discussed the equipment you'll need to start your own seeds, and this week, I'd like to talk about exactly which seeds to start indoors and how to do it.

Nearly all seeds can be started indoors, but that doesn't mean they all should be. The seeds of some plants are best started by directly seeding them in the garden rather than going through the effort of starting them indoors. Beans, cucumbers, squash, corn, carrots, turnips and beets immediately come to mind as seeds that should be sown into the garden when the time is right — in fact, many root crops grow best from seeds sown directly into the garden. Check the seed packet for sowing instructions and follow them appropriately.

For seeds that are best started indoors (tomatoes, peppers, basil, eggplants and cole crops for starters), begin by examining the seed packet for instructions regarding light requirements. Some seeds require light to germinate, while others do not. While experimenting with this can be fun, you risk lowering germination rates if you don't follow the packet's specific instructions. If it says to cover the seeds with a quarter inch of potting soil, do it. If it says, “sprinkle on the surface but don't cover,” then don't cover them.

The next thing to consider is the timing. Knowing exactly when to start your seeds is a fine art indeed. Starting them too early inevitably leads to leggy, overgrown transplants. Starting too late, means they'll be puny and unfit for life in the harsh outdoors. To figure out all this timing stuff, turn again to the seed packet. Every seed packet should include information on “days to germination” (how long it usually takes from the day you plant the seed until the resulting seedling breaks the soil surface) and “days to maturity” (how long it will take from germination to harvest for plants started by direct seeding, or how long it will take from the day you transplant the seedlings outdoors until harvest for plants started indoors). Keep in mind that both numbers are calculated under ideal conditions and can fluctuate by several days.

To determine when to sow the seeds of tomatoes, for example, add the days to germination (seven) to days to maturity (75 days on average) — resulting in 82 days from seed to harvest. If you'd like to start harvesting tomatoes on July 10, sow the seeds indoors around April 19 (82 days before). Many seed packets also will help with this by telling you to sow the seeds indoors a certain number of weeks before your last expected frost date (for tomatoes it will often recommend six weeks). I always caution against starting seeds too early; it is one of the biggest mistakes new seed-starters make.

After all the sowing dates have been determined and you're ready to roll, start by filling your planting vessel with potting soil up to the rim. Tap the container on a hard surface once or twice to settle in the soil. Sow your seeds at the recommended depth and cover them with more potting soil if necessary. Water the newly planted seeds with a spray mister bottle, being careful not to wash them away. Cover the seeded container with a clear plastic covering, a sheet of Saran wrap, or a clear dry-cleaning bag to keep the humidity up and prevent the soil from drying out. Place it on the seedling heat mat I described in last week's column and wait.

As the seeds begin to germinate, remove the plastic covering (leaving it on could mean developing fungal issues). At this point, you can use a fine-shower sprinkling can to water the seedlings. Now is when you'll also need to begin supplying them with supplemental lighting. Those fluorescent shop lights I discussed last week should be positioned 2 to 4 inches above the plant tops and should be turned on from 18 to 24 hours per day. You'll need to raise them as the plants grow. I set my lights on a timer so I don't have to remember to turn them on and off every day.

To increase air circulation around growing seedlings, you can use an oscillating fan aimed just above the plant tops. Run it for two hours in the morning and two hours in the evening, again, on a timer. It also will strengthen plant stems by creating movement.

Continue to water your seedlings as necessary, and every two to four weeks, fertilize them with an organic liquid fertilizer, like liquid kelp, fish emulsion or compost tea, diluted to half strength.

When your seedlings have developed two or three sets of leaves, it's time to separate your babies and transplant them into larger containers. Use sterile potting soil again, but this time you can choose one not specifically formulated for seed starting.

When outdoor planting time arrives, harden your seedlings by gradually acclimating them to outdoor conditions. About three weeks before planting them outside, move the seedlings to a shady area outdoors for a few hours every day. Do this for several weeks, gradually exposing them to more sunlight and wind. This gradual adjustment to outdoor conditions helps the plants deal better with the move.

Horticulturist Jessica Walliser co-hosts “The Organic Gardeners” at 7 a.m. Sundays on KDKA Radio. She is the author of several gardening books, including “Grow Organic” and “Good Bug, Bad Bug.” Her website is

Send your gardening or landscaping questions to or The Good Earth, 503 Martindale St., 3rd Floor, D.L. Clark Building, Pittsburgh, PA 15212.

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