The following is an excerpt from "Sugar Snaps and Strawberries: Simple Solutions for Creating Your Own Small-Space Edible Garden" by Andrea Bellamy (Timber Press, 2010). The excerpt is from Chapter 7: Sowing Seeds.
Time to get your hands dirty. Starting seeds is easy. You just push a seed into the dirt, right? Sure, the how is simple, but the when requires a bit more thought.
Plant a seed too early, and cold temperatures will prevent it from germinating. Plant it too late, and it won’t have time to grow up and produce fruit before winter chills hit. Catching that planting window is the key to seed-starting success.
Of course, you don’t have to start all your edibles from seed: buying ready-to-plant veggies from the nursery does have its merits. Whichever route you choose, this chapter will teach you how to get your garden started.
I never fail to be amazed by seeds—or the incredible bounty that I can harvest from what began as tiny, shriveled specks. Some beginning gardeners regard seed starting with a healthy dose of fear, but the fact is, seeds are designed to survive, thrive, and eventually reproduce. We simply help them along by providing a little loving care.
Where to sow
You can start seeds in two main ways: Start them indoors in little pots, to be transplanted outdoors once the time is right. Or plant them outdoors in the place you want them to grow and mature into their full-grown selves.
If planting them directly outdoors sounds easier, it is—at least for you. Starting seeds indoors can be more involved. But some vegetables, especially warm-season crops such as tomatoes, melons, eggplant, and peppers, need to be started indoors, because they require consistent warmth and a long growing season. In most climates (I’m not talking about you, California), by the time the soil is warm enough for their seeds to germinate outdoors, these plants won’t have time to produce a crop before chilly autumn temperatures roll around again. So we start them indoors, weeks before the last frost date, and then transplant them outdoors after temperatures warm up. Not all seeds can or should be started indoors, however. Some plants, notably root crops such as carrots and beets, do not like to be disturbed once they have, well, put down roots.
If you’d rather not start your own seeds, you can buy vegetable seedlings, also known as starts or transplants, from a nursery. But many gardeners start their plants from seeds for a couple good reasons. First, seeds are almost always cheap, and sometimes free. You can get 500 lettuce seeds for the same price as a six-pack of lettuce transplants. Second, finding seeds for the more uncommon types of vegetables is easier than finding transplants (think purple carrots and wrinkled heirloom tomatoes).
Seeds require moisture, warmth, light, and oxygen to germinate. But like most things in gardening, it all starts with the soil.
• Soil. Seeds prefer a light, airy medium that provides good air circulation and allows for effortless root development; it should hold moisture but should not get soggy.
If you are planting directly outdoors, give your planting bed a once-over with a cultivator to provide the loose, fine soil seeds require. This is also a good opportunity to amend your soil with compost.
If you’re starting seeds indoors, use a seed-starting mix, a light and fluffy, sterile blend of peat or coir, perlite, and vermiculite (or make your own using an equal blend of the three). A sterile mix is considered ideal, because garden soil and compost contain living organisms that can introduce diseases. They might also contain weed seeds.
• Containers. You can start seeds in pretty much anything, from recycled yogurt containers to storebought plastic cell packs. Plastic pots work fine for seed starting. Forget those cute little terracotta pots at the nursery—they allow the soil to dry out too quickly, and ditto for compressed peat pellets. Newspaper pots are great for plants that don’t like to have their roots disturbed, since you can plant the entire pot. And you can make them yourself. You can find instructions online (search “newspaper seedling pots”) and make a free supply of seed-starting pots in no time. Don’t use them for seeds that require a long period of time indoors before planting out, because the newspaper may break down before plants are ready to transplant. Plantable pots made of newspaper, coir, or other biodegradable material must be thin enough (and must break down fast enough) for plants’ roots to be able to penetrate the walls with little effort.
Choose containers that will allow your seedlings room to develop, or be prepared to move plants into larger homes if they outgrow their pots before they are ready to go outside.
• Moisture. Maintaining consistent moisture is crucial to success in seed starting. Your aim is to keep the soil consistently sponge-damp; fluctuating from bone-dry to sopping wet is torture to sensitive seedlings. Use a watering can with a fine rose nozzle, a spray bottle, or, even better, water from below. Place your pots in a tray or sink filled with 1 in. (2.5 cm) of water and let them soak it up. Don’t let them sit in the water for too long—half an hour should do the trick.
• Warmth. Some seeds, such as peas and other early-season vegetables, prefer cool soil. Others, such as peppers and cucumbers, prefer a slightly balmier climate. Most seeds germinate best in temperatures from 60° to 75°F (16° to 24°C). But don’t crank up the heat (and your gas bill), because there are better ways of providing warmth to germinating seeds.
Sit your seed trays on top of the fridge, on a sunny window ledge, or on a warm oven. You can move the trays after the seeds have germinated—although some plants, such as peppers, prefer extra warmth even after they have sprouted.
It may be worth investing in a special heating mat that provides warmth from the bottom (which seeds love), or rigging up your own bottom-heat source. Some people position a 40-watt incandescent light bulb under a metal shelf or run outdoor Christmas-style rope lights through (clean) kitty litter, and then set their seed trays on top. My mom sets her trays on top of 1-gallon black plastic nursery pots with low-voltage shop lights inside. However you swing it, be careful not to start fires or electrocute yourself!
• Light. After seedlings have emerged from the soil, they need a lot of light; without it, they grow leggy—tall, thin, and weak. Providing the light they want—14 to 16 hours a day—will probably be your biggest challenge in indoor growing.
A bright, sunny window will do, but this is not ideal (cloudy days combined with early spring’s lack of daylight hours equal a light deficiency). If you want to get serious about seed starting, you can set up your own little grow operation using fluorescent lights. Believe it or not, you can use a couple of 40-watt fluorescent tube lights to keep your seedlings happy and healthy.
Hang the light from your ceiling, balance it on the backs of two chairs, mount it under a shelf—however you do it, make sure you can either move the light or the plants up and down. Start out with the light about 3 to 4 in. (8 to 10 cm) above the seed trays and gradually increase the distance to about 4 to 6 in. (10 to 15 cm) as your plants grow.
Step-by-step: how to sow seeds
1. Moisten the soil before you sow. It should be damp but not wet—like a wrung-out sponge. This applies to outdoor (direct) sowing, too.
2. Fill your containers with soil mix. Tamp it down gently, leaving 1/2 in. (12 mm) or so of space at the top.
3. Check the seed packet for information on how deep to sow the seed. As a rule of thumb, seeds can be planted at a depth of about twice their diameter; thus large seeds such as beans will be sown deeper than miniscule carrot seeds. It is better to err on the side of planting too shallow, however; plant too deep and the seedling won’t be able to reach the soil surface.
4. If you are sowing larger seeds in containers, poke a hole into the soil using a chopstick or pencil, place one seed in, and cover it with soil. For smaller seeds, sprinkle them on top and scratch them in. Depending on the size of your container, you might plant two to six seeds. Planting extra provides a fallback in case one or more fails to germinate. If you are sowing outdoors, sow a row by creating a trench with the edge of your trowel, and then scatter or place seeds evenly along it. Follow the spacing directions on the seed packet. Of course, you don’t have to plant in straight lines. Blocks or natural-looking drifts also work.
5. Label your containers or rows if you are sowing more than one type of seed.
6. Place the containers in a warm, bright area, and wait. (If you cover your trays with a clear dome or plastic bag, you may not even need to water again until the seeds germinate.) Some seeds germinate in days; others take weeks.
Seedling Feeding and Thinning
A plant’s cotyledon, or seed, leaves are first to emerge from the soil. These leaves provide the growing plant with nutrition until its true leaves appear (the third and fourth leaves to develop) and it’s time to fertilize. Sterile seed-starting mixes provide no nutrients, so after true leaves appear, feed your seedlings weekly (and weakly) with a liquid kelp/fish emulsion combo (or add kelp one week and fish the next). If you added a little compost or worm castings to your seed-starting mix, you can skip this step.
At this stage, you need to make tough decisions about what to do with all those little seedlings that have germinated. Seedlings need breathing room for both roots and shoots, and keeping them tightly packed together means none of them will thrive. So you must thin them out, cutting off the weakest at soil level. Aim to leave only one seedling per 3 in. (8 cm) pot; in larger pots you can leave two. Thinning does not have to be a total waste of little plants: most seedlings are delicious in a salad.
In outdoor gardens, thin seedlings in stages; if you thin to the final spacing distance too early, you may wind up with fewer plants than you intended, since bugs and slugs can make suppers out of the remaining tender seedlings.
Your indoor seedlings have had a pretty sheltered upbringing. To put them directly outdoors without preparation would be like us getting dropped in Antarctica without a jacket. Seedlings started indoors need to go through a toughening-up regime called hardening off before being planted outside.
Hardening off involves setting your pots of seedlings outdoors for increasingly longer periods of time to get them accustomed to the elements. Start by setting them in the shade—direct sun would be more than they could take—for about an hour. During the next several days, repeat this little field trip, slowly lengthening their outdoor visits, but bringing them back indoors for the night. You will also start introducing them to sun, and eventually (after a week or so), you can leave them out overnight.
Feel free to skip a day if the weather is particularly brutal. Cold frames, like mini greenhouses, allow you to skip all this schlepping inside and out. Just plunk your plants into the cold frame for two weeks, opening the lid for longer and longer periods of time each day.
After seedlings have been hardened off, they are ready for more permanent digs. Whether you are planting them in the ground or in a larger container, it’s great to see your babies planted in their forever homes (even if you do end up eating them after a few weeks).
To start, dig the planting hole slightly deeper and about twice as wide as the plant pot. Unless you have already amended your soil with compost or a complete organic fertilizer, do this now, before adding the plant.
Squeeze the sides of your pot to release the plant. You may need to tap the rim gently. Try not to handle the seedling. If you must, hold it by its leaves—ideally, by its seed leaves, if it still has them—never by the stem.
Place the seedling in its hole, making sure its soil is level with the surrounding soil. Do not bury the stem, except in certain cases, such as tomatoes, which benefit from being planted deeply. Gently fill in the remainder of the hole with soil, and water well. That’s it!
Fruit trees are often sold as bare-root stock, which is exactly what it sounds like: the roots are bare, with no soil around them. Understandably, bareroot stock is sold in the winter months when the trees are dormant.
If you purchase bare-root stock, soak the roots overnight prior to planting. Dig a hole (or choose a container) approximately twice the diameter of the tree’s root system, and loosen the soil on the walls of the hole to make it easier for the roots to spread. Next, put some soil back into the hole, mounting it up in the center. Spread the tree roots out over the mound. If you’re planting a grafted tree such as a dwarfed apple, make sure that the graft union (the bulge where the rootstock meets the trunk) will be 2 to 3 in. (5 to 8 cm) above the soil line. Fill the hole with loose soil, pressing it down with your hands as you go. Water well. Many young fruit trees benefit from staking at the time of planting.
When to plant
A few factors determine the best time to sow or plant, including the plant’s own nature. Is it a coolor warm-season edible? Cool-season crops can handle lower temperatures and are usually planted in early spring or spring, or in late summer for an autumn, winter, or even spring harvest. In contrast, warm-season crops like the heat and are usually planted in late spring or early summer after the soil is nice and warm.
The average last frost date in your area is a huge factor in determining when to plant. Many seed packets say things such as, “direct sow at the time of last frost,” or “start indoors 4–6 weeks prior to last frost.” Go online to learn your area’s average last frost date and to get a better idea of when your growing season starts.
After your seeds or starts are in the ground, the magic begins. But don’t just sit back and watch the radishes grow—not yet, anyway. The next chapter tells you how to keep those precious little seedlings happy and healthy—and ultimately, ready for eating!
Taken from Sugar Snaps and Strawberries: Simple Solutions for Creating Your Own Small-Space Garden (c) Copyright 2010 by Andrea Bellamy, Photography by Jackie Connelly. Published by Timber Press, Portland, OR. Used by permission of the publisher. All rights reserved.