What to do in the garden in May

By Sharon Lampton, Master Gardener

Ah, spring! One day it's 90 degrees, the next it's 60. One day is windy, the next calm. One day is bright with clear blue skies; the next is overcast and feels like January. Gardeners don't know if they are coming or going. At least this spring we have a spectacular display of roses to inspire us to greater achievements.

This is the month we need to do a lot of work to prepare for the warm months ahead. It's time to feed azaleas and rhododendrons, and carefully remove spent blossoms. Feed roses after their first big bloom, then again about every four weeks for the rest of the summer. Aerate and fertilize your lawn.

Check your irrigation system. Most fertilizers require water to work efficiently, so make sure the irrigation system covers all the areas to be fertilized.

Since most of us haven't used our sprinklers since last fall, all sprinkler heads should be checked for blockages and cleaned as needed. Also look for clogged emitters in your drip system. It's also a good time to check the output of your irrigation system. The rule of thumb is that one inch of water will wet one foot of soil. To check the output of your sprinklers, set clean cans or cups in various places around your yard, and turn on the sprinklers for the amount of time you normally water. When finished, check the depth of water in the can. If it's less than one inch, you need to increase the amount of time you water. Most plants prefer long, deep watering rather than short, shallow watering, to encourage root depth. Remember that even drought-tolerant plants need to be watered the first year or two, while their root systems are forming.

Sow these seeds directly into your garden: beans, cucumbers, pumpkins, summer squash, carrots, Swiss chard, endive, turnips, lettuce, peas, radishes, corn and melons. Transplant seedlings of tomatoes, eggplants, basil and peppers. Flowers that start easily from seed include zinnias, sweet peas, nasturtiums and sunflowers. Remember to install any supports you will need when you plant. Adding them later can damage the plants' roots.

Thin the fruit on your trees. This will prevent limb breakage as the fruit matures and the remaining fruit will be larger.

Carefully apply mulch around seedlings after they have emerged. Apply mulch to all of your flower and vegetable beds. A layer of three to four inches of mulch will retain moisture in the soil and reduce the number of weeds. Keep mulch one foot away from tree trunks and six inches away from the trunks of shrubs and rose bushes.

Monitor your garden for pests and diseases. Common pests this month include aphids, ants, and scale. A strong spray of water easily controls aphids. If you see ants on trees, put a band of sticky material around the trunks to trap the ants as they climb. Like aphids, scale excretes honeydew that attracts ants and causes growth of sooty mold on fruit, nut and olive trees and grape vines. To control scale, apply horticultural oil sprays after irrigation, but never in midday heat or when the plant is water-stressed. Continue to pick or trap snails, slugs and earwigs. Keeping the garden tidy will help control these pests by giving them fewer places to hide. Hoe or hand-pick weeds when they are small and easy to deal with - never let them get to the seed stage in your garden.

This is a busy time in your garden, but there is always time to stop to smell the roses.