Starting seeds indoors for vegetable gardens

Christo Brock plants seedlings of mesclun mix in Christo Brock plants seedlings of mesclun mix in his neighbor Julie Stern's organic garden. Photo Credit: Los Angeles Times / Ricardo DeAratanha

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Jessica Damiano Jessica Damiano, Newsday columnist

Jessica Damiano is a master gardener and journalist with more than 20 years experience in radio, television, print ...

It's time to start planning vegetable gardens, and those starting seeds indoors should already have their grow lights and cell packs dusted off.

That's the easy part.

Knowing exactly when to start which plants, however, can be a bit mystifying, as some will grow to transplantable size sooner than others. Start too soon, and plants will be weak, leggy and spindly by the time it's safe to move them outdoors. They'll struggle to regain strength and may actually end up behind those started later. Start too late, and your harvest will be delayed, sometimes even inhibited, from reaching its full potential.

Seed packets typically instruct gardeners to start seeds a given number of weeks before the last frost date. On Long Island, the average last frost date is April 15, but it could be later. I used a range of April 15-23 in determining these guidelines for the ideal time to start each of these seeds indoors, give or take five days on each side of the given date.

SEED -- START DATE -- TRANSPLANT DATE

Broccoli -- March 9 -- April 5

Cabbage -- March 9 -- April 5

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Cauliflower -- March 9 -- April 5

Kale -- March 9 -- April 5

Lettuce -- March 9 -- April 5

Eggplant -- March 25 -- May 20

Peppers -- March 25 -- May 20

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Tomatoes -- March 25 -- May 20

Cucumber -- April 10 -- May 5

Squash -- April 10 -- May 5

These seeds are best sown directly outdoors:

SEED -- DATE

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Lettuce -- March 17

Peas -- March 17

Radish -- March 17

Spinach -- March 17

Arugula -- March 25

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Carrots -- April 5

Beans -- April 20

Corn -- April 20

Money-saving tips

Start seeds in clean yogurt containers, egg cartons or even eggshell halves (rinse and carefully poke a tiny hole in the bottom with a pin).

If reusing last year's cell packs, disinfect them for 10 minutes in a 90/10 water/bleach solution.

Visit newsday.com/gardening101 to learn how to make a newspaper seed pot and your own potting mix.

Seed-starting steps

1. Fill containers with moist, soilless seed-starting mix (never use garden soil; it's too dense and can contain organisms that could lead to disease) and sow three or four seeds per cell, pressing gently.

2. Keep moist. Watering through holes poked in the bottom of containers will avoid accidentally washing away seeds and reduce the risk of fungal diseases. This is easily done by placing containers in a tray filled with water. Cover cells tightly with plastic wrap.

3. Set in a warm, cozy spot, out of direct sunlight. Check periodically and water as needed. Keep an eye out for "damping off," an airborne fungal disease that causes a white mold layer on the soil surface. If this happens, scrape it off and allow soil to dry completely between waterings.

4. When seedlings sprout, remove plastic wrap and place containers in bright sun or, even better, under fluorescent lamps, for 14 hours daily. Temperatures of 65-75 degrees will ensure best results for most plants. Remove weakest seedlings.

5. A week before transplanting into the garden, begin to "harden off" plants by placing them outdoors each day. Pick a shady spot protected from wind and start with a half-hour, adding an hour of exposure each day until they're getting about eight hours of outdoor exposure daily. Continue watering.

Plant some TLC

It's almost spring, and the garden is waiting. Here are seven chores to undertake over the next two months.

1. Clean up

Clean up debris from last year's annuals. Perennials that should be cut back now include ornamental grasses, echinacea, black-eyed Susan, aster, astilbe, balloon flower, butterfly weed, campanula, heuchera, delphinium, dianthus, foxglove, globe thistle, hosta, joe pye weed, lamb's ear, lupine, Russian sage, sedum and coreopsis.

2. Nourish

Next month, when you're planting perennials (and in May, when annuals are installed) add a handful or two to new planting holes. As soon as new growth appears on perennials, apply a slow-release organic fertilizer, taking care to follow package directions precisely.

3. Weed

Pull weeds early and often, as soon as they pop up, before they go to seed. This is most easily done when soil is damp, either after rainfall or irrigation.

4. Plant and divide

Space annuals and perennials according to plant tag recommendations to accommodate their mature sizes. Crowding plants might provide instant gratification, but it will encourage mold and mildew diseases and, for perennials, lead to division and transplanting chores sooner than necessary. In general, perennials take three years to reach maturity, true to the adage: The first year they sleep; the second, they creep; the third, they leap! Many perennials should be divided every three years, before they start looking shabby or become crowded. Generally, perennials that bloom in summer and fall should be divided in spring, and spring bloomers should be divided in autumn.

5. Plant edibles

It's vital to know your soil's pH before planting food crops to ensure nutrients from the soil and amendments will be absorbed by plants. Most vegetables require levels between 6.2 and 6.8 to thrive; herbs prefer a neutral 7.0. Test the soil as soon as it's workable, and add lime (to raise pH) or sulfur (to lower it) if necessary. Till compost into the top 6-8 inches of soil and, for vegetables (not herbs) apply organic fertilizer at planting time at the rate recommended on the package.

6. Lawns

Sharpen mower blades and set to 3 inches. Begin mowing when grass is more than 3 inches tall, never cutting more than a third of the existing height at once. Allow grass clippings to remain on the lawn for a natural source of nitrogen.

Got bare spots? Work on them next month, applying seed once a week and watering twice a day until new growth fills in. Add lime if indicated by a pH test (ideally, the range should be 6.3-6.8), but don't fertilize until Memorial Day.

7. Mulch

Mulch retains soil moisture, smothers weeds and maintains an even soil temperature. There are many mulch materials available, including shredded bark, wood chips, salt hay, gravel, pebbles, geotextile fabrics and black polyethylene film. Black polyethylene is often used under gravel walkways to block weeds, while geotextile fabrics can be used in new vegetable beds (cut slits to insert plants), and organic materials like bark and wood chips decompose over time to enrich the soil. Apply your choice of mulch after the soil has warmed, no sooner than May.

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