Tuesday, June 23, 2009

Gardening Basics: Seeds and Seedlings


Hybrid vs. Heirloom Seeds

Virtually every packet of garden seeds sold in retail stores (and on the Web) is hybrid. A hybrid is the offspring of two pure-strain parent varieties that were crossed. Hybrids are developed for various desirable qualities: greater resistance to disease and insects, higher yields, ability to thrive in hotter or colder climates, etc. But if you save seeds from your crop and plant them, you'll find that they don't breed true. They might not sprout, or they'll have a low germination rate. The plants that do emerge could be sickly or low-yielding. Even if the fruit is abundant, its appearance and quality will be variable, and probably worse than the first generation you raised with the original store-bought seed. Bottom line: you cannot rely on hybrids to produce two or more generations of consistently good crops. You have to keep buying new packets of hybrid seed, or new hybrid seedlings from your local nursery, every season. Given the prospect of major economic disruptions and shortages, this might not be a good strategy.

The alternative to hybrid seeds is heirloom seeds. Heirlooms, as the name implies, can be saved from each harvest to raise the next generation of crops. The key is to prevent cross-pollination with crops of a different variety (e.g., keeping the plum tomato in your yard from crossing with the cherry tomato growing ten feet away) and master good seed-saving practices. I'll address these topics in a future post.

Two highly rated heirloom seed sources (per the Garden Watchdog) are Victory Seed Co. and Baker Creek Heiloom Seeds.

Caution: I've read that some seed companies sell hybrid seed that is labeled "heirloom". Do your research before buying (e.g., ask other gardeners about their experiences with the seller's products) to make certain you will get what you pay for.

To get some idea of the tremendous variety of heirloom tomatoes, peppers and eggplants on the market, see this collection of photos.


Seed Storage

Pay attention to the shelf life of your seeds. Allium seeds (onions, leeks, garlic) are only good for a year, after which germination rates drop steeply. Solanaceous seeds (tomatoes, peppers, eggplants) will last for several years, as will cucurbit seeds (cucumbers, squash, melons). The newer the seed, the better it will perform.

Store seeds in a cool, dry, dark location, sealed in paper envelopes.

Here is a list giving the shelf life for various kinds of vegetable seeds.


Growing Vegetables from Seed

Here is an instructional video for growing vegetables from seed in pots.

My own method for growing tomatoes, peppers, and eggplants is to plant the seeds in starter pots filled with enriched potting soil, two months before the end of frost season. The seeds are planted 1/4 inch deep. The pots are placed on a window sill for adequate light, and the soil is kept slightly moist. Moisture control is vital. Over-watering causes seeds to rot, or promotes the growth of fungus that weakens and kills newly sprouted seedlings (damping off disease). As the seedlings grow, I transplant them into progressively larger pots to keep them from becoming root-bound. When all danger of frost is past, I plant them outside in the raised beds, with some tinfoil wrapped around the base of the stems to protect the young plants from cutworms.

The roots of young cucurbits (cucumbers, squash, melons) are easily injured. Transplanting them in any way which disturbs the roots will often kill them. Plant the seeds in peat pots or peat pellets. When the roots begin to grow through the bottoms of the peat container, plant the entire container in the ground (the peat will break down and become part of the soil). As an alternative, plant the cucurbit seeds directly in the ground after the end of frost season.

Whenever planting seeds directly in the ground, plant several seeds for each plant you intend to raise. Seeds packets often give instructions for the best number of seeds to plant for a certain linear footage of row. This allows for loss of some seedlings to insects or birds. Thin out all but the strongest seedlings, and make sure the plants are optimally spaced so each has enough room to develop a healthy root system.

Rapid growth in seedlings is promoted by applying "starter" solution (a type of liquid fertilizer), which is either watered into the soil or sprayed onto the leaves. Manure tea is one example, used with great success by organic gardeners. Other starters are seaweed-based, like Medina.

Mulch the Soil to Raise Healthy Plants

To help your crops flourish, cover the soil with a layer of mulch (click here to read about various types of mulch and their uses). Mulching conserves soil moisture, prevents erosion, and shields delicate feeder roots, which run just beneath the soil surface, from the sun's heat. I've used hay and dried grass cuttings for mulch, both with good results.

Container Gardening

If you have too little space in your yard for a garden, you can also raise crops in containers. This article gives the basics for vegetable container gardening.

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