There’s plenty to do this week in your garden.
Late May frosts, snow or hail can harm annual and vegetable transplants. Remember that even though the average last frost date for metro Denver is May 15, there is a wide variation around the average, and frosts can occur even into June. To be conservative, sow seeds directly now and wait until June to plant transplants. Remember to water all seeds regularly until plants are well established.
Early slicing cucumber and pickling varieties can be planted now. Plant five to six seeds in a hill or plant in a row to grow up a fence. Cover with 1 inch of soil and water regularly for best yields and flavor.
Other vine crop candidates to seed are zucchini, squash and pumpkin if you want to grow your own for Halloween. Look for pumpkins that mature in 90 days.
Want a green, leafy vegetable all summer long? Plant heat-tolerant Swiss chard now for young or mature cooked greens from July to October. Swiss chard has many colorful varieties that add interest to a vegetable or flower garden.
Tomatoes’ growth is inhibited by cold soil. Use black plastic mulch tacked over beds to help warm the soil before you plant, or plant along the south side of a building to take advantage of reflected heat. In other areas, create a temporary plastic greenhouse over the plant, or use a water wall. Be sure the plastic does not touch the foliage, and ventilate during the heat of the day. Protect plants from any danger of frost.
Mulch new flower and vegetable plantings to help moderate soil temperature, retain moisture and limit weed growth. Mulch also gives a finished look to your beds. Use wood chips, bark, dried leaves, evergreen needles or dried grass clippings. Choose heavier mulch where wind is a factor.
Deadhead lilac bushes when bloom finishes for better flowers next year.
Jennifer Reinbrecht is a Colorado State University Cooperative Extension master gardener in Denver.
