5.10.10

Seeds for the Future

One of the almost-forgotten phases of plant production is seed culture. In our modern plant world, we hear so much about growing tissue-cultured plants ( formerly called "cloned" plants), division-propagated and cutting-propagated plants that growing plants from seeds seems almost archaic. Why ? There are actually some good reasons, and of course, some downsides to growing plants from seed.

seeds growing in sterile media


Seed culture produces variations in the resulting plants. Depending on what results you want, this can be good or bad, depending on whether you want a crop of identical plants or whether you actually want some variation. Many interesting plant varieties arose from seed-cultured plants. Dwarf, giant, variegated and unusually colored plant types can arise in a batch of seedlings. If you want to sell 100,000 identical plants, however, seed culture may not be the way to produce them. For such consistency, tissue cultured plants would be wisest. Growing plants from seed can be fun, but also requires some prep work to insure success.



seeds growing on sterile gel medium

"cloned" tissue culture plants
One of the most important aspects of seed culture is cleanliness of potting materials. In our climate, fungi are everywhere and can rapidly ( and I mean RAPIDLY) kill seedlings. Sterile pots, clean soil, and clean growing conditions help a lot in succeeding with seed culture and fighting fungus problems. Think about hospital maternity rooms for infants versus adult life conditions and you'll get the idea for growing seedlings.

 Pots can be sterilized by dipping them in a solution of 1 part bleach and 10 parts water for an  hour. Clean soil means bagged potting mix or soil sterilized by steam sterilizing. Clean growing conditions mean pots that are off the ground on clean racks, covered and protected from rain and weed incursions, in shaded areas, and away from foot traffic. If you are growing seeds in the ground, try covering the germinating area with black plastic sheet for 3-4 months before you grow seeds there. The sunlight will greatly heat up the soil, helping to retard diseases and insects. Remove the plastic very close to planting time, or weed seeds will blow onto the clean soil. Some seeds need full sunlight to grow well, please check the seed packets for germinating instructions. 

seeds growing in sterile medium in poly bag
    
Once you have these clean conditions, you can sow a great many seed types by planting them just under the soil surface and keeping the soil or potting medium moist. One of the classic and successful methods to grow seeds in pots is to use bagged African Violet soil in sterile pots, with seeds sown just under the soil surface, and covered with 1/4" of milled sphagnum moss. You can buy milled sphagnum moss from seed companies. The moss acts as a natural sterilizer against fungus spores, and keeps the soil surface moist without being soggy.


sterile bagged soil

 A good general rule to follow is to place the seed pots in "bright shade", an interesting oxymoron which translates to light without direct sunlight.  You can judge light levels by seeing if your hand casts a shadow in the chosen area. If you see a shadow, it's too much light. If you use a light meter, look for fern light levels, or if you are technically inclined, look for levels under 1000 footcandles.


Once you have a forest of seedlings, then what ? I often joke that now is a good time to call all your gardening friends and see how many plants they want ! Sometimes you can end up with too many plants, but there always seem to be people who want the extras. Wait until the seedlings are a few inches tall then carefully separate them into cell-pack trays or small pots. If you leave the seedlings all crowded together, diseases can ravage them fast, and they'll compete with each other for food and water. Separating seedlings allows more light to reach the stems, and permits you manage the plants by pinching or pruning to make compact well branched plants.



Milled sphagnum moss
courtesy of repotme.com


Once the plants have grown to 6 or 7 sets of leaves, they can be planted into the ground or into pots. The hardest part of growing a plant is now over, and you can look forward to watching it mature. 
One of the greatest achievements in horticulture is to grow a plant from seed to flower, have the plant set seed, and grow the next generation from the plants you started yourself. 

Craig Morell
Pinecrest Gardens  




                     

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