Email  Print

GARDENING

Starting from seeds: A great way to grow more plants on the cheap—or too much trouble? It all depends.

In the prosperous, technology-focused ’90s we would never have dreamed how many new gardeners would start growing vegetables at home, or even how huge the passion for flower gardening would become. (And could we have predicted that Garden Walk Buffalo would gain us national gardening fame?) It’s a logical next step that more and more gardeners would want to go all the way—growing their plants from seed. The trouble is, lots of people try, and many are disappointed. To increase your odds of success, let’s take a look at what’s worth growing from seed, when, and where.

Plant your seed—outdoors or in?
For success with seeds, we can all save a lot of time by sorting out which ones are best planted directly in the soil (called direct seeding) and which perform better if you plant them as seedlings or transplants. And then you need to know the timing. A lot goes into those decisions:

How long does it take for plants to get from seed to harvest? Some crops like collard greens just don’t have a long enough growing season here, so transplants are the only way.

What conditions does the seed need to germinate and grow? A cold period? Warm soil? Lots of spring rain? For example, there’s no point in putting warm-season seeds like squash in the cold spring soil; better to wait.

What’s the survival rate for a given crop planted as seeds versus transplants? Some seeds are fragile or quick to rot so seedlings make more sense; other crops don’t transplant well so seeds work best.

It sounds complicated. But farmers, gardeners, and scientists before us have figured out the following groupings. Use them to decide about seeds or transplants for the most common vegetables and easy annuals. (For plants not listed, read seed packets or research to check it out.)

Cool-weather crops to grow directly from seed outdoors: Plant these as soon as the soil is workable in your area; they tolerate some frosts and freezing spells. Every gardener can succeed with these.

Vegetables: beets, kale, lettuce, mesclun and other gourmet greens, peas, potatoes, radishes, spinach, and Swiss chard. (Note: potatoes aren’t exactly grown from seeds but rather start from cut potato pieces with a little “eye”—where the sprout comes from.)

Flowers: alyssum, bachelor’s buttons (Centaurea cyanus), bells of Ireland, forget-me-not, larkspur, Shirley poppies (Papaver rhoeas), snapdragons, and sweet peas.

Warm-weather crops to grow directly from seed outdoors: Plant these seeds only after the “last-frost” date in your area—in WNY, from May 21 to June 1. These are also easy for new gardeners, as long as the soil has warmed up.

Vegetables: beans, cucumbers, melons, squash, pumpkins.

Flowers: calendula, castor bean, cleome (spider flower), cosmos, hyacinth bean, marigolds, morning glories, nasturtium, nigella (love-in-a-mist), sunflowers, zinnia.

Cool-weather plants to plant outside as seedlings when the soil is workable: You can buy these seedlings in a farmers’ market or garden center, or start the seeds inside under lights.

Vegetables: broccoli, Brussels sprouts, cabbage, cauliflower, Chinese cabbage

Flowers: dusty miller (Centaurea cineraria), diascia, kale/ornamental cabbage, Nierembergia, osteospermum, pinks (Dianthus chinensis), viola.

Warm-weather/tender plants to plant outside as seedlings: Be sure the danger of frost has passed and the soil is warm.

Vegetables: celery, eggplant, peppers, sweet potatoes, tomatoes. (Often the vine crops such as squash and pumpkins are also readily available as seedlings.)

Flowers: coleus, dahlia, licorice plant (Helichrysum petiolare), sweet potato vine (Ipomoea), and many more. (Most newer annuals or tender perennials do best planted as seedlings; many are also patented or do not grow true from seed.)

Planting outdoors: Timing is (almost) everything.
Now that you know the difference between cool-season and warm-season plants, the precise timing is still critical. Instructions in books and on seed packets always recommend how many weeks before or after the last frost date to plant seeds or seedlings. In our region the last average frost date is around May 21, meaning that often there is a frost around June 1st. Still, there are many variables. In Buffalo, Amherst, and other northtowns locations, or in very sheltered yards, frosty nights end sooner; those folks might take a chance on mid-May plantings. In very exposed areas, and in the southtowns, frosty nights often linger all through May. So plan accordingly: Figure your last average frost date, and count the weeks forward or backward to decide your planting dates.
For planting seeds outdoors, timing isn’t quite everything however. A few seeds need special treatment before they will germinate. Some need a moist cold period before they will sprout; others need soaking, scratching, or nicking (called scarification) to penetrate their tough shells (notoriously, morning glories). Then every seed has a particular depth for planting (and some germinate right on the soil surface). Good seed packets will tell you all this information, along with books and internet research (using regional, science-based sources).

Growing under lights
Very few seeds grow well in trays on a windowsill. Most home windows don’t provide enough light; if they do it is uncontrolled and sometimes a hot spell overheats the seedlings. So except for a few radishes or marigolds in a cup, indoor seed-starting calls for supplemental lighting or a greenhouse, sunroom, or Florida room. Then you need the right supplies.

Artificial (supplemental) lighting: All plants aren’t alike. You’ll grow a geranium differently from a coleus or African violet. Each type needs light with a particular color spectrum, intensity, and duration. Most vegetables and flowering annuals need a balanced spectrum of red-to-blue lighting, 14 to 18 hours of light daily, and high intensity (light placed within inches of the seedlings). Be sure the system you choose permits adjustment of the light level as the plants grow. Many light set-ups are available in a wide range of prices, but lots of home gardeners succeed with homemade set-ups. Do not use house lamps; they are too hot for plants.

Types of bulbs: Fluorescent: Typical office (cool fluorescent) bulbs are fine for many houseplants but are too cool for seedling growth. If you can set up two fluorescent tubes—one cool white and one warm white—you will do well with your seedlings. Full spectrum fluorescent bulbs that mimic sunlight are excellent choices if you can find them.

HID (high intensity discharge): Lamps used by professional growers; expensive and use too much electricity for most of us. They include metal halide, high-pressure sodium, and mercury vapor lights.

The rest of the requirements: Containers: Flats, pots, milk cartons, egg baskets (biodegradable or plastic)—all work if conditions are right for the seedlings.

Seed-starting mix: Use professional, well-draining, soilless potting or “seed-starter” mix. Do not use old potting mix (with the nutrients all gone) or real soil.

Heat: Some seeds germinate best with bottom-heat, so some growers use heat mats. Mostly they are not necessary; sometimes the top of the refrigerator works. Room temperatures of 60° to 70° F suffice for most plants, with a nighttime drop of 10°.

Fertilizer: Once seedlings emerge, a houseplant or indoor fertilizer will be necessary; use half-strength for the first three weeks.

Water: Use tepid water, bottom watering, or misting for fragile seedlings.

Humidity/ventiliation: Plastic covers help to increase humidity during germination, but remove them after seeds sprout. Air circulation is necessary to prevent fungus problems.

Is growing under lights for you?
It’s a joy to grow your own tomato from seed; it’s disappointing when the plant is so leggy it droops, or you put it outside too soon and it dies. (The most common home gardener mistake is starting tomato plants way too soon indoors!) Growing under lights is a commitment, and offers some challenges. Do try it, but don’t count on the produce for your family’s survival, at least during the learning phase. If you set up a system and plan your moves, you will surely enjoy the process and probably see some flowers and taste the best veggies ever.

What is worth doing for sure? Grow something from seed this year, indoors or out. And invite the kids to help.

Sally Cunningham is a horticulturist, garden writer, lecturer, and TV gardening expert. She is also a consultant at Lockwood’s Greenhouses in Hamburg, where she provides gardening lectures—including vegetable gardening classes in spring. (See www.lockwoodsgreenhouses.com.)