How to Grow Plants from SeedHow to Growing Plants from Seed
Become your own nursery by starting your own seedlings
Just when I’m beginning to feel that winter is never going to end, the first seed catalog arrives in the mail. Almost as welcome as the first snowdrop, it marks the beginning of a delightful time of year for gardeners—a chance to consider the many plant possibilities and anticipate next season’s garden.
Starting the Seeds, Germination and Preventing Damping-off
Starting the Seeds
Container options include plastic cell packs, peat or plastic pots, soil blocks (which are subsequently planted directly into the ground), and recycled items such as milk cartons or yogurt containers with holes punched in the bottom. The plastic trays with corrugated bottoms available from garden centers are ideal for holding the containers.
You can use either a soilless mix or potting soil, but the planting medium must be able to absorb and hold moisture, be fluffy so it won’t form a crust, and be free from weed seeds and soil-borne diseases, which can cause damping-off (see “Dirty, rotten scoundrels,” below). After filling containers, press soil down gently but firmly; don’t pack it too hard. Water until it’s moist but not soggy.
There are several different seed-sowing techniques you can employ. An easy, dependable method is to plant several seeds in each individual cell pack or container. Very tiny seeds, and those requiring light to germinate, should be pressed into the surface of the soil but not covered. For most other seeds, make a small hole with a blunt pencil or similar implement and plant the seed about twice as deep as its size.
Label each container with a waterproof marker and record the date, type, and variety name. Keep a separate record of the source of the seeds and germination requirements, leaving room for future notes. Over the years, this record book will be a valuable resource.
Cover the containers with clear plastic (such as dry-cleaning bags) to preserve moisture; for seeds that need to be kept in the dark to germinate, use black or green garbage bags. If the light is required, site seeds where they’ll receive indirect light. For seeds needing warm temperatures, there are several options. My favorite spot used to be on top of an older, energy-inefficient refrigerator. Alternatively, you could use heating cables (available from garden centers), or put the containers under grow lights, leaving them on continuously. Start with the lights well above (about 30 cm) the containers, and put a thermometer under the plastic. Keep lowering the lights until the desired temperature is reached. I generally check every 20 to 30 minutes or so initially.
Dirty, Rotten Scoundrels
Several fungi that live in the soil can cause damping off, a disease that attacks stems at the soil line, causing seedlings to rot and fall over; overwatering makes seedlings more susceptible. To help prevent damping off, let the soil surface dry out between waterings. If stems become infected, however, cut out the affected seedlings immediately and discard.
Other preventive measures include applying a one-time dusting of cinnamon powder after seeds are sown and watered (before seeds sprout); watering or misting with weak camomile tea; or using commercial products such as No-Damp. -Anne Marie Van Nest.
Growing and Transplanting to the Garden
Inspect the containers regularly for signs of germination. As soon as the seeds sprout, remove the plastic and transfer seedlings to an area with bright light and a cooler temperature: grow lights left on for 16 hours a day are ideal or place plants in a sunny southern window.
Keep the soil damp but not soggy, using room-temperature water. For soilless mixes, feed with half-strength fertilizer (with low, roughly equal nitrogen, phosphorus and potassium numbers) when the first true leaves appear, then twice a week thereafter. For potting soils, start fertilizing two weeks after the leaves appear, fertilizing every 10 to 14 days thereafter.
Once the seedlings have their first true leaves, thin to the most vigorous seedling per container. When the leaves begin to touch, transplant to a larger container.
Transplanting to the Garden
Before planting out, move seedlings to a sheltered location outside. Gradually introduce them to cooler temperatures and direct sunlight, starting with one hour of morning sun and increasing it by an hour or so daily. Bring seedlings inside if frost threatens. Don’t plant heat-loving varieties outdoors too soon, as they will never recover from the shock or, worse, die.
Dig a hole several times larger than the root ball and mix in lots of compost and some organic fertilizer. Place the seedling in the hole; fill in with extra soil, firming it gently, then water. Keep it moist until a root system is established. If frost threatens, cover vulnerable plants.
Named hybrid varieties of perennials, such as daylilies, irises, and peonies, will not come true from seed. Although the offspring may not be the same as their parents, it can be exciting to see what you get.
While some perennials are easy to grow, others require more effort and patience than vegetable seeds. Some take weeks to germinate and others take a long time to grow to flowering size (peonies, for example, can take five or more years). Many perennial seeds need a period of cold that mimics the winter they’d experience germinating outside, so you need to condition those ones in the refrigerator.
Veggies are easy to start from seed. Some, however, such as cucumbers, melons, okra, and squash, don’t like to be transplanted; these should be started in peat pots (biodegradable pots are fine, as long as they break down fairly quickly) or individual containers instead of cell packs, removing the plants carefully during transplanting so their roots are not disturbed.
Providing Essential Light
Grow lights provide essential light that some seeds need to germinate. Whether you’re starting off small or trying to rival your local nursery, there are models available to fit your space and your budget. Here are three styles to help bring the sun indoors.
If you’re starting off with just a few seeds, a full-spectrum, compact, fluorescent light is your best bet. This model (above), available through Urban Gardening Essentials, is energy-efficient and easy on the wallet. Its standard-sized base means you can use an existing light fixture or purchase any inexpensive fixture you please.
For more ambitious seed projects, Hydrofarm’s Green Thumb Light System takes full-spectrum fluorescent technology to the next level. A one-touch height adjustment makes controlling light intensity a breeze. Available in either two- or four-foot-wide units, this system includes an aluminum stand, light fixture, and two fluorescent tubes.
Floralight’s three-tier system can accommodate thousands of seeds and
up to 240 pots that are 10 centimeters wide. It has extra-wide reflectors that evenly distribute light and waterproof garden trays that allow for easy bottom watering. The system includes six Ultra Gold full-spectrum fluorescent tubes, which emit both blue (for vegetative) and red (for flowering) light spectrums.
Table of Contents
- 1 How to Grow Plants from Seed
- 1.1 Starting the Seeds, Germination and Preventing Damping-off
- 1.2 Growing and Transplanting to the Garden
- 1.3 Providing Essential Light