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Seed Starting 101

Martha Stewart Living, Volume 81 July/August 2000

A seed, by design, is programmed to grow -- satisfy its basic requirements, and the rewards will be immeasurable. Although some types of seeds are best sown directly in the garden, many annuals and vegetables, especially frost-sensitive ones that require a long growing season, are ideal for starting indoors and transplanting out once the weather warms. Starting seeds indoors gives you an early start on the season and allows you to try more varieties than will be available locally. Use our seed starting worksheet to help you keep track of the process.

Seeds: Purchase high-quality seeds packed for the current year. Before using them, test old seeds, and always store seeds correctly for later use.

Pots: Choose containers based on your needs and preferences. Thoroughly clean terra-cotta or plastic pots before reusing them for seed starting. Use large clay or plastic pots with drainage holes, also known as community pots, for starting a group of seedlings. Peat pots, cell packs, and pellets are naturally sterile, and because they can be directly planted outdoors, they are ideal for plants with delicate roots. For large sowings, use plastic cell packs for convenience.

Soilless mix: Use a sterile soilless mix that is about one part milled peat moss and one part vermiculite with some perlite. Most commercial seed-starting mixes also have enough fertilizer for about 2 weeks. Never use a mix containing topsoil or compost.

Planting trays and covers: Use plant trays under pots for bottom watering, and top seeds with a clear cover. Clear plastic wrap can also be used to cover germinating seeds.

Labels: Always label seeds with the variety and date sown.

Grow lights: Choose full-spectrum fluorescent lights that can be positioned directly above seeds and raised as seedlings grow. Grow lights not only provide the light required for healthy development, but they also warm the soil, speeding germination.

Before starting seeds indoors, find out the last frost date in your area; then read seed packets to learn how many weeks before this date the seeds should be started and when they should be planted outdoors. Calculate your sowing date accordingly.

How to Sow Seeds
1. In a large bucket or tub, gradually add tepid water to sterile soilless mix until it is evenly moist but not wet.

2. Cover the drainage holes of clay or plastic pots with a small piece of newspaper, and fill containers to the top with moistened mix. Tamp down mix so surface is firm and level, about 1/2 inch from the top.

3. Using a dibble or pencil, make holes in mix, about twice as deep as the seed is wide, and sow seeds at the depth and distance recommended on the seed packet. Cover with more mix unless otherwise specified. Seeds that require light to germinate can be sprinkled on the soil surface.

4. Label pots with the type of seed and the date sown. Bottom-water containers by setting them in trays filled with an inch of tepid water.

5. Cover containers with clear plastic before placing them 2 to 3 inches below grow lights. For seeds that require darkness to germinate, use an opaque cover, and set them in a warm spot such as the top of a refrigerator

Even for the experienced gardener, the sight of that first seedling stretching upward is magical. Once you've sown seeds indoors, check containers daily for new shoots, then follow the steps below.

1. Keep the seed-starting mix moist until germination is complete and the emergence of new seedlings slows markedly or stops. Remove covers, and if you haven't already, place seedlings under grow lights, leaving lights on about 14 to 16 hours per day. Continue to bottom-water.

2. As soon as seedlings produce their first true leaves, begin watering with a balanced fertilizer or fish emulsion diluted to one-quarter strength. Prick out seedlings planted in community pots, and transplant them to individual pots or cell packs filled with moist soilless mix. Lift seedlings by their leaves rather than by their delicate stems.

3. When soilless mix dries, water transplanted seedlings using a water breaker or mister that produces a gentle spray. As seedlings grow, raise grow lights, keeping them 2 to 4 inches above plants.

4. If necessary, transplant seedlings to larger pots as they grow. Before planting outdoors, gradually harden off seedlings: Two weeks before transplanting, place seedlings outdoors for a few hours at a time, gradually increasing their time outside until they are acclimated.

Comments (7)

  • pottingblockguru 28 May, 2008

    For those of you concerned about the environmental impact of using peat in your blocking mix: All studies are aimed at the environmental impact on EUROPE, not Canada. Why? Because there is minimal impact on the harvest of peat bogs in Canada, says Canadian officials. In Canada, peat bogs are a renewable resource able to regenerate themselves faster than the depletion. Check out my web site for more soil block info, www.pottingblocks.com, The World's resource for soil block gardening.

  • lisaziegler 8 Apr, 2008

    Glad to see that soil blocking is getting more well known--I have been blocking for 11 years as a commercial cut flower farmer and no other seed starting method compares. Thanks Martha! Lisa Ziegler, The Gardener's Workshop

  • Off2sing 27 Mar, 2008

    Seed Blockers are amazing. I ordered on through Peaceful Valley in CA. GrowOrganic.com
    I saw it in Martha's gardening issue and wow. It's great.
    I only got the 4 2 " block. Wish I had gotten a bigger one, but first time out. Who Knew?
    I'm going to order the standup one and really rock some potless starters.
    Suzi
    Stone Feather Farm, VA

  • schoolrn 27 Mar, 2008

    WHERE DID YOU SAY TO ORDER THE TOOL TO MAKE YOUR OWN SEED STARTING POT?

  • Bewitched4ever 27 Mar, 2008

    you can also buy a bale of straw hay and leave it bundled together and just take a knife and carve holes in the top and plant with a little soil and just leave them in the the hay and let them go. I get the most beautiful plants and they grow right in the hay.

  • bellepauly 26 Mar, 2008

    BrittTekla is corrrect. Please do not use Peat, its not just destorying wildlife but history aswell, Peat bogs in Britian have been found to hold Bog Mummies in perfect condition. If we carry on removing these areas you are not only destryoing wildlife but you maybe destroying a countries History.

  • BrittTekla 29 Feb, 2008

    Taking peat from the wetlands is actually having a grave effect on the environment: "Some environmental organizations and scientists have pointed out that the large-scale removal of peat from bogs in Britain, Ireland, Finland and Canada is destroying wildlife habitats. It takes centuries for a peat bog to regenerate."
    A better alternative is to go to a petstore and buy reptile bedding made from coconut coir. Coconut coir is a waste from the coconut industry and is cheaper.