Every sunny windowsill in my house is filled with flats and pots of seedlings: tomatoes, peppers, eggplant, cosmos, hellebores, snapdragons, marigolds, basil and more. As in life, there are pitfalls along the way.
If you use peat pots, keep them moist at all times. Otherwise the peat pot pulls moisture out of the soil, leaving your new seedlings high and dry. Any roots that have gone through the pot will be strangled if the pot dries out.
Peat pellets don't provide much in the way of nutrients, so seedlings will need to be potted into something else once they germinate and their true leaves appear.
Fit the seed to the container. Don't try to germinate large pumpkin or squash seeds in tiny peat pellets. My favorite container: six-packs and 4-inch pots I've saved from buying plants at the nursery. I choose the soil, and there's enough room in them for the plant to stay there until time to be transplanted into the garden.
These are some common seed-starting problems:
Leggy seedlings: Not enough light. Once seeds are up, they need light and plenty of it. If you use artificial lights, make sure the lights are just a few inches above the seedlings. If you depend on windowsills or sunny rooms, make sure the seedlings get as much light as possible. Rotate the flats regularly so all seedlings get light. Take seedlings outdoors when the weather is mild so they get direct sunlight. Be careful not to leave them out too long. Run your hand across the seedlings gently several times each day this helps them develop strength.
Seeds don't germinate: Too much water and the seeds will rot. If the soil is too cold, the seeds will rot. Keep pots inside, use bottom heat or wait a few weeks and try again.
Seeds don't grow after they germinate: Besides light, seedlings need nourishment. If you are planting in peat pellets or using a soilless mixture, replant the seedlings into a soil mixture that has some nutrition in it. A weak liquid fertilizer feeding will help, but, really, the best solution is to repot into soil with more nutrition.
Seedlings are ready for garden but it's too cold outside: You started too soon. Pot them into bigger containers. Give them lots of light. It's best to wait on things like cucumbers, squash, sunflowers and beans until the weather outside is mild instead of frightful.
Damping off: If seedlings suddenly become weak and topple over, the culprit is usually a fungal disease called damping off. The cause is overwatering and not enough air circulation around plants. Seedlings do not recover. Water in the morning; make sure the soil isn't soggy. Replant.
Camellias are in full bloom. Buy them now when you can choose the colors you like. Keep spent flowers cleaned up off the ground to prevent spread of petal blight.
Prune summer blooming shrubs now: oleanders, hydrangea, and butterfly bush.
Plant bulbs for summer bloom: dahlias, begonias, gladiolus, lilies and more.
It's time to plant potatoes. They come in many colors and shapes.
Spray for brown rot on plum, apricot and almond and other fruit and nut trees when buds open. To control leaf curl on peaches and nectarines, spray with fixed copper or copper sulfate. If you can only spray once for leaf curl, the best time is when the buds start to show pink.
Watch for aphids on roses, iris leaves and bulb foliage. Wash then off with a strong jet of water.
Plant dahlia tubers.
All herbaceous perennials (those that die back to the ground each year) should be cut back before new growth starts. If clumps are crowded, divide them.