I could be the poster child for Seeders Anonymous. I have a black thumb when it comes to starting seeds indoors. Every few years I get ambitious about using plants started from seed, drool over seed catalogues, spend entirely too much money and order more seed than I could possibly have room to start indoors. Once the seed arrives, I procrastinate, struggle with making a decision on how to start the seeds, and then ultimately forget to water at a crucial time in the seedling’s development. My first steps in overcoming my problem is to admit I am powerless over this ineptitude and plead with my partner to start the seeds for me—so far I have had little success.
Face it, growing a garden—flower or vegetable—from seed can be tricky: if it weren’t garden centers would have little reason to exist than to sell seed. The upside to using seed to start plants is that the entire world of plants is at your disposal. Nurseries can only offer a tiny percentage of the plants that live in this world for sale as live plants. If a plant isn’t available in the trade, the only way you can grow it is if you can start it from seed. Starting plants by seed brings us much closer to the cycles of life than most any other activity we might choose. Here is an acceptable form of sexual voyeurism with a triple ‘G’ rating. We have the opportunity to observe the unfolding of a miracle—that a plant can encapsulate its full being in one small package and make life possible for animals on this planet. This is serious stuff, rewarding the gardener with a glimpse into the natural world.
I like to be rewarded for my efforts, so I’m at it again with my attempt to grow from seeds. The place to start is where everything in gardening should start—with a plan of course. Sitting fireside, seed catalogue in hand, we can dream of fields of flowers, baskets of ripe fruit and rafters full of drying herbs, but we’ll never get there if we don’t set some goals and guidelines. Take some time before tackling the seed lists to consider the following:
Experience and Skill Level: I have experience with no resultant skill level. There are differing levels of skill required to propagate different species of plants. One thing I like about the Thompson and Morgan seed catalogue is that they list the level of experience and care required to achieve best results—something I was unable to find on their website. In general, most annuals are pretty easy to start by seed, perennials take more effort, and woody plants may require advanced techniques. Of course there are exceptions to the rule, but one of the reasons we eat the foods we eat is because they are easy to propagate. So, if its veggies and pretty flowers you want to grow, chances are they will be relatively easy.
Room to Grow: Obviously, you need space to grow the plants but another consideration is whether the seed needs to be started before it is safe to plant outdoors. Many of the vegetable plants we grow are tropical or sub-tropical, requiring warm soil temperatures in order to grow. Seeds for tomatoes, potatoes, peppers, and eggplants won’t germinate in cool soils. In this region soils don’t get warm until June, so in order to grow these plants and get fruit before the hard freeze in fall, the plants need to be started indoors. Most seeds need a warm, moist environment to germinate and then require plenty of bright light to grow into seedlings. A simple method to germinate seeds is to start them on top of the refrigerator where it tends to be warmer—you can use anyplace that isn’t in direct sun, is consistently warm but not so hot it dries out the seeding medium too fast and most important for me—is someplace out of the way, but not out of mind–you’ll need to check on them daily. Once the seeds germinate they need a place in the sun or bright lights to develop from seedlings into viable plants. This is what takes some space and why timing is such an issue.
Timing: Dependent upon the climate conditions where it originally evolved, a plant has preferences for growing conditions—some of which are non-negotiable. One element that is pretty much cast in stone is the time it takes for a plant to reach maturity, and as with vegetables, the time it takes for the fruit to ripen. When the growing season—the time between freezing temperatures in spring and fall—is short, the gardener needs to select a cultivar that will ripen before fall frosts.
For example, corn, depending on the cultivar, takes anywhere from around 70 to over 120 days from planting to harvesting. In Denver, the growing season runs between mid-May to mid-September—somewhere around 120 days, but corn is sub-tropical in origin, so it needs soil temperatures of at least 60 degrees. Most years, soil temperature hasn’t reached optimal temperature by mid-May, so a cultivar that needs 120 days probably won’t yield much before air temperatures drop below freezing and kill the plant in the fall. This is because the seed will sit in the soil until the soil warms enough for the seed to germinate, which could take several weeks.
Ways to cope with the constraints of temperature include selecting a cultivar that requires a shorter time to reach maturity—in the 70-90 day range, warming soil by the use of a heating cable or Wall O’ Water, starting the seeds indoors or buying seedlings from a garden center just before planting time. To start seeds indoors count back 5-6 weeks from your area’s last frost date to determine when to begin—in Denver that would mean starting seed sometime around the beginning of April.
You can start earlier, but the seedlings will probably get leggy unless you have a greenhouse or adequate grow lights. Non-tropical vegetables such as peas, brassicas, and greens like cooler temperatures and tend to bolt once the heat of summer sets in. Peas are planted in this area around St. Patrick’s Day, spinach about the same time.
Cultural Requirements: Of course the cultural requirements—light, water, soil & nutrition—are important to your selection of seeds to grow. Most vegetables need full sun, lots of consistent water, and well drained, nutritious soil with neutral pH. You can get away with planting leaf and root crops in part sun and there are selections of vegetables that are more drought tolerant by their nature, but water is generally another non-negotiable requirement.
Vegetables can develop a bitter taste if they are not watered consistently, partly because the minerals that these plants need to develop fully are water soluble—no water, no nutrients. Tomatoes develop blossom end rot when there isn’t a consistent amount of water to transport calcium to the fruit during development. If you have a space you want to use that won’t receive regular water, it won’t be a good place for vegetables and you should put drought tolerant plants there instead.
When growing vegetables in containers where the amount of soil is limited, so the amount of available water is limited, you must be vigilant about keeping the soil moist in the container if you want vegetables that taste good. I’m not a fan of bitter tastes and our broccoli sometimes becomes inedible if we have an extreme heat wave or a malfunction in the drip system.
Preferences: You might look at this as a half full/half empty kind of philosophy—you can choose what you like, then eliminate the plants that won’t grow under the limitations you established under the considerations above. Or you could limit the offerings first, then choose the plants you like.
Gracie is a landscape designer and master gardener with nearly eight years professional experience.