Spring has arrived and (hopefully) by mid-month we will see our last frost date. Keep in mind that there is always a danger of frost at night, so be sure to watch the weather forecast and be prepared with plastic or cloth sheets to cover any tender seedlings you have planted in the garden. As hard as it is, waiting to plant until Memorial Day may be the best bet, especially for heat-loving plants.
After danger of frost is past, you can plant all your annuals. Late light frosts may harm the tenderest annuals such as impatiens, so keep plastic sheets, burlap bags or bed sheets handy to cover them. Hardy annuals such as geraniums and petunias can tolerate a light frost.
Most perennial flowers only need an annual application of compost or a light sprinkling with a complete organic or slow-release fertilizer to keep them thriving. Those that may need a mid-summer feeding include astilble, garden phlox, mums, shasta daisies, delphinium, and lilies.
Fertilize spring blooming bulbs early May. Snip the dead flower heads but do not cut back the foliage until it has withered and yellowed.
Cut back the dead top growth of perennials and perennial grasses. Leave about 3 or 4 inches of stems.
Sow seeds for frost tolerant perennials as soon as the soil has thawed, dried, and begun to warm. Some seeds will not germinate until the soil is quite warm, so check directions for soil temperature on the seed pack.
When planting new perennials, if the weather has been dry, lightly water the soil the day before you plan on planting. You want it moist, but not soggy. Water the plants in their pots a few hours before planting.
Make holes for new plants wide and shallow. Set the root-ball on undisturbed soil so that your plant doesn’t sink as the soil settles, making it susceptible to crown rot. Don’t mix granular fertilizer into the soil at planting time as it can burn tender young roots.
If your tulips are not in the right place, now is a good time to move them. Carefully dig and replant bulbs and their attached foliage in full sun and well-drained soil.
Don’t rush to plant heat-loving plants like tomatoes, peppers, eggplants, and melons. Wait until the soil is warm and the danger of frost is past. Plants that are exposed to too much cold weather early in their lives may never fully recover. Black plastic mulch laid in the garden bed a several weeks before planting will help warm the soil.
Plant seedlings of cool-weather vegetables such as broccoli, spinach and cabbage. Plant sugar snap and snow peas directly in the ground.
For a fall harvest of cabbage, kale, and Brussels sprouts, sow seeds in pots indoors or in a cold frame around the time of the last frost and transplant to the garden about 4-6 weeks later.
Organic mulch like straw is a great way to keep down weeds and conserve soil moisture, but it also keeps soil cooler, so hold off spreading it until the soil has warmed up.
Bush beans bear relatively quickly and for just a few weeks, so if you want a steady, moderate supply, make small succession plantings every two weeks until midsummer. Pole beans take longer to begin bearing, but produce a steady harvest over a longer period and take up less garden space as they climb up their supports.
Sow seeds or plant seedlings of annual herbs such as dill, chervil, fennel, and cilantro directly in the garden where they are to grow. Basil is very tender, so wait for all danger of frost to pass before planting it.
Install upright structures such as teepees, trellises, ladders before planting seeds for climbing veggies such as pole beans, cucumbers, vining squashes, and gourds. Stabilize the structure so it doesn’t blow over in a storm. Plant seeds in soil at the base as directed on the seed packet.
Transplant shrubs and trees after the soil thaws out and dries, while the weather is still cool and before new growth begins.
Apply dormant spray to fruit trees before the buds swell and air temperature will be above freezing for at least 24 hours.
Remove any winter protection wraps from your tree trunks to avoid harboring insects.
Apply a liquid or slow release granular fertilizer to spring blooming shrubs after the flowering is complete.
Established azaleas often do not require additional fertilizer. Test soil for nutrient levels and pH. If the soil is low in nutrients, lightly scatter only a few tablespoons of an acid-forming, granular, slow-release fertilizer on soil under the shrub.
Prune dead lilac flowers as soon as possible after they wilt before brown flower heads go to seed. Prune to shape shrub. Next season’s flowers form early in the lilac branches. So late pruning will remove next spring’s flowers.
Forsythia blooms on the previous year’s wood. Just after the golden yellow flowers die, prune to shape the shrub and fertilize.
Water lawns deep to promote deep roots and develop drought tolerance. The best time to water lawns is early morning. The goal is to apply 1- 3/4 inches of water per week if the weather is dry.
After the first mowing, apply fertilizer. Include pre-emergent for crabgrass if necessary. Crabgrass seed generally germinates after the soil temperature has reached 50 degrees, and requires about 5 consecutive days of 50 degree soil temperature.