This is the time of year to start those seeds.Growing plants from seeds is reasonably cost effective and is a way of acquiring plants that don’t normally appear in the markets. As we discovered last season with the tomato blight, it is also a way of acquiring disease free plants. Most serious gardeners have at one time or another started plants from seeds. Each grower has his own methods and over the years develops special techniques and tricks to facilitate the process.
It is possible to start seeds in almost any container. Those into using biodegradable materials can wrap their own posts from newspaper or go with the peat pots or pellets. These are only for those who like to water frequently. They dry out quickly and are difficult to rehydrate. Pots can also be made out of paper towel rolls. Cut them into appropriate sized lengths and plug the bottoms with paper towels. These can be conveniently lined up in trays.
Easiest to use are the plastic containers that are provided by restaurants for leftovers; once closed they are miniature greenhouses that require little care. They will however overheat if left in direct sunlight. They are also getting harder to come by. A good substitute is a shallow plastic pot that can be slipped into a plastic bag. For large numbers of seedlings a plant tray works fine. Line the ones with holes in them with newspaper to keep the potting medium in place. They can be covered with plastic or slipped into a dry cleaner bag. Any method that prevents soil from drying out facilitates the process, especially when plants are being grown in the house where it may be difficult to water without making a mess.
Eventually, the plastic has to be removed. The plants will get too large and if they are grown in sunlight they will burn. At this point the best way to keep them moist is to put shallow trays or containers under them. Bottom watering is best when the seedlings are small. Top watering will often flatten the seedlings. If care is taken the trays will provide sufficient water without overwatering. They should be emptied after 24 hours if too much water remains.
Most sources will insist that seeds should be started in sterile soilless mixtures. This is the easiest method of preventing fungal diseases that will destroy seedlings. It can get very expensive if you are growing large numbers of seedlings. There are a number of ways of getting around this. It is possible to sterilize soil in the oven. Place the damp soil mixture in an oven heated to 180ºF. Cover it tightly with aluminum foil and insert a meat thermometer. It should be sterile when it is held at 180º for 30 minutes. This can be a smelly procedure especially if you let the soil reach 200º at which point it starts to burn. It is also possible to sterilize soil in the microwave. Two pounds of wet soil can be microwaved in a plastic container or bag for approximately 2 minutes.
Using a good grade of potting soil will usually work, although most sources insist that only soilless mixtures are appropriate. Potting soils don’t claim sterility but they are probably treated to at least destroy weed seeds. The process seems to destroy other undesirables, as well. Cheaper brands or top soils are more likely to contain bacteria and fungi and are not suitable for seedlings. Sprinkling peat moss on the top of the soil will lower the pH around the seedlings and prevent the fungi from growing. Vermiculite is also supposed to work, creating a physical barrier around the seedlings in which the fungus doesn’t grow.
It is possible to make an adequate soilless mixture that is less expensive than the type that can be purchased in small bags. It can contain varying amounts of Perlite, peat moss, and ground sphagnum moss. The Perlite can be replaced with sand or vermiculite. Fungi are unlikely to grow in this mixture.
Most seeds germinate best at room temperature or warmer. The small plants though will grow better at cooler temperatures. The sturdiest plants that I have ever grown were started under lights in a fruit cellar that was maintained at less than 60ºF. Seedlings should be kept cool.
The latest whimsy is the suggestion that the small seedlings be brushed periodically with the hand. This movement simulates the action of wind and is supposed to keep the stems sturdy. This need for movement is also allegedly why it is ill advised to stake small trees.
The length of time a seed remains viable varies with the seeds. Allium seeds frequently last only one year. Tomato seeds are good for 4 years or longer and some morning glory seeds will last for decades. This is also subject to storage methods. The germination rate drops as the seed ages, so it is handy to have a method of testing. Place 10 seeds between moist paper towels. Place the packet in a lidded container that allows some light through as many seeds need light to germinate. Mark the container with the name of the seed and date. (No, you are not going to remember what it is.) The number of seeds that sprout is the percent of germination you can expect from the seed. If you choose to use them, you can compensate for the drop in germination rate by planting more seeds. It has been my observation over the years, that older seeds do not produce the sturdiest of plants. Use fresh seed if possible.
Do you have a special way that you germinate seeds or handle transplants? Share them with your fellow gardeners on our forum.