Starting Seeds Indoors
Giving them a Head Start
Gardeners in northern climes use a variety of means to cope with the brevity of their growing season. When the last frost might arrive as late as May or early June, seed planting must be delayed also. With some quick-growing plants, this isn't too much of a problem. But many vegetables and ornamentals will benefit greatly from a little head start.
Starting seeds indoors can be an imperative for certain plants in particular climates. Even as far south as Washington, D.C., where we reside and where the last frost usually arrives in early April, getting an early start can make a big difference. Moonflower vine, Ipomoea alba, a tender perennial that I mentioned in the column on stratification, will not germinate until the average temperature is close to 70 degress F (21 degress C). This usually occurs in mid-to-late May. However, if I start it indoors I can transplant it outside several weeks earlier. This provides me almost another month of nightly blooms.
The Big Three
Seeds started indoors require the same basic conditions as those started outside. But since their environment must be artificially maintained, it takes a little more attentiveness. Just as for all plants, the three basic requirements are soil, light and water. But in each case there are special considerations.
Avoiding the Fungi
It is essential that the soil you use be sterile. One of the great banes of seed growing is a fungus commonly known as Damping-off Disease. The spores of this fungi are ever present in soil and the conditions of indoor gardening seem particularly advantageous to its propagation. It can wipe out hours of hard work in a matter of days, killing off your nascent cornucopia before it's had a chance.
To avoid this scourge you must use a sterile soil or, even better, another sterile medium. Some gardeners like to use their own soil. This involves sifting out any larger clumps and stones and then sterilizing it in an oven. This is a lot of work and the results are probably no better than using a commercially available starting medium. These usually consist of some combination of vermiculite and peat moss and are often referred to as "soil-less." When buying a seed-starting medium, make sure it has been sterilized! This should be clearly indicated on the packaging. After it has been thoroughly moistened, the medium can be placed in flats, peat pots, dixie cups, egg cartons, etc. The size of the container will depend on what type of plant you're growing, and often experience is the best gauge.
Keeping Them Stout
When seedlings receive insufficient light they become tall and spindly or "leggy." Seedlings need a lot of light. Even if you have a window that receives full sun, you might need to supplement it with artificial light. If you are using only artificial light, you'll need a great deal of it. Because our visual system is so sophisticated, people rarely realize the incredible quantitative difference between natural and artificial light. It would be all but impossible to recreate the intensity of direct sunlight. To compensate, you'll need much longer growing days. Use bulbs that are specifically made for growing plants and place them just a foot or so above your seedlings. You'll want to keep these lights on at least 14 hours a day. Fluorescent tubes are ideal because they won't produce as much heat which can quickly dry out your seedlings.
Keeping a Watch on Moisture
The third ingredient is moisture, and this is the one that will require the most attention. You want to keep the medium moist, but not let it become wet or soggy. In general, it is best to water from below, allowing the medium to soak up the water like a sponge. To promote germination, many gardeners cover the flats or pots with plastic wrap. This keeps the planting medium both warm and moist, but must be removed as soon as the plants sprout. Otherwise, you risk suffocating your young seedlings.
At this point you will need to keep an eye on things to maintain the proper moisture. If you have a totally artificial setup you will probably be able to predict how often you'll need to water. If you're using a sunny window sill, you'll need to watch more closely. Placing the containers
on a raised bed of gravel spread across the bottom of a large pan with a small amount of water can help to prevent your seedlings from drying out. Make sure the water level is below that of the gravel so that the plant containers rest on the gravel and not on the water.
When They're Ready
It is important not to start seeds indoors too early.
If they outgrow your flats or small pots you might try thinning them and
transplanting the largest to bigger pots, but for the most part you want
to plant them outside just as they become large enough to survive transplanting.
This is generally four to six weeks after sowing, when they have at least
two sets of true leaves. In other words, if you're aiming to plant the
first week of May, you probably shouldn't be starting seeds any earlier
then mid-March. Toward the end of this period, you may want to provide your
seedlings a little food in the form of a weak, water-soluble fertilizer.
Again, experience, both yours and others', is the only sure guide to what
will work for you. Always be willing to experiment. And good luck on your
- -- Sesbania Tripeti
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