April is an exciting month for gardeners. It's the start of a new and promising growing season full of potential. Bedding flats, vegetable plants, trees, ground covers, roses, shrubs, potting soil, fertilizers, spades, rakes, forks, everything but grass seed (too early), fill row after row of our favorite garden centers. The daffodils and iris (planted last fall) have been up for weeks along with a few early wildflowers. I have even had a few hummingbird scouts buzz through my garden; a sure sign of spring!

* PLANTING COOL SEASON VEGETABLES: Lettuce, broccoli, onions, spinach, and cauliflower can be transplanted into the garden. It's really a bit late for seeds, though you can try with some short season varieties. Beets, carrots, and radishes can still be sown by seed, but look for varieties that can be harvested in 50-70 days, before the high heat of June and July sets in. It's still a little early for tomato plants to be set outdoors unless you are willing to give them extra protection on the cool nights still to come. April's weather can be tricky (we've had freezing temperatures the first week of May for two years in a row), and young transplants are especially vulnerable. If you wait too long, however, your cool season vegetables will be trying to mature during the hottest, most arid part of our growing season. If you miss the cool season planting, aim for warm season vegetables planting in late May and early June, and plan your lettuce and beet planting for fall. The Cooperative Extension Service has a pamphlet called Vegetable Varieties for Arizona available at the Willcox or Sierra Vista Extension Office.

* FERTILIZING: Your trees, shrubs, roses, and flower beds need a fresh supply of nutrients to support spring growth and build strength for the long growing season ahead. Nitrogen, phosphorus, zinc, and iron are four of the critical plant nutrients often lacking in Arizona soils. Of the remaining nutrients, carbon, hydrogen, and oxygen are absorbed from water and air, and potassium (or potash) is readily available in our soil as are many of the micronutrients (nutrients needed in small quantities only). The two nutrients to concentrate on when fertilizing your plants in the spring are nitrogen and phosphorus.

1. Nitrogen promotes deep green color, top growth, and root development. It usually needs to be applied every year because it is leached from the soil by rain and irrigation water. This same leaching action, however, makes nitrogen easy to apply. Simply broadcast (spread lightly and evenly) a nitrogen fertilizer on the soil surface and water it down. Corn, broccoli, cauliflower, potatoes, lettuce, carrots, and beets usually require additional nitrogen. Do not give extra nitrogen to peas, tomatoes, or squash since it will encourage excess top growth and poor fruiting.
2.  Phosphorus is essential for early seedling growth and later will promote flowering and fruiting. Unlike nitrogen, phosphorus moves very slowly through the soil and best results occur when it is worked into the top two inches of the soil or banded two inches below seeds or transplants at planting.
3. Iron and zinc are micronutrients and usually are not applied unless a plant has a history of iron or zinc deficiency, or is presently showing signs of such deficiency. Foliar sprays (sprays applied to plant leaves) of zinc and iron are the quickest and most effective application methods, although iron chelate can be worked into the soil around the plant. Zinc; tends to react with calciferous soil (like ours) making it unavailable to plant roots.

* You will need to apply fertilizer several times during the growing season with the last application in August. Remember, chemicals contained in fertilizer react with elements in the soil to form salts (nitrate, phosphate) which your plant can then absorb. Too much fertilizer can kill a plant, especially if it is high in nitrogen. Read commercial fertilizer labels carefully, and always measure and apply fertilizer according to instructions. The Cooperative Extension Service has a pamphlet called Fertilizing Home Gardens in Arizona available at the Willcox or Sierra Vista Extension Office.

* PREPARING FOR PESTS: After a few pest free months we are about to be invaded by ants, spiders, aphids, and codling moth - and they will be hungry. So, be prepared. Practice good gardening habits such as removing dead vegetation, keeping after weeds, and companion planting. You may want to consider introducing some biological controls into your garden in the form of beneficial insects such as lacewings, praying mantis, and parasitic wasps. Eggs and larvae of some beneficial insects are available in gardening catalogs. Look for our "Pest-of-the-Month" feature for more hints.