August 25, 2012

1 - Fall is time to plant garlic in New Mexico.

Yard and Garden August 25, 2012

Q.

When is it time to plant garlic?

Myers

Via NMSU University-wide Extension

A.

Garlic is planted in September and October in northern New Mexico and October and November in Southern New Mexico. It grows well in our cold weather, maturing in the heat of summer. NMSU Extension Publications - Guide H-234: Garlic Production in New Mexico and Research Report-717: Varietal Evaluation of Garlic in New Mexico, and Circular 457-B: Growing Zones, Recommended Crop Varieties, and Planting and Harvesting Information for Home Vegetable Gardens in New Mexico may be helpful to you.

Brown leaves on trees in late summer may indicate overwatering.

Q.

We have several bur oak trees that have been planted for 1 to 5 years that are 6 to 12 feet tall. After producing leaves this spring, several now have leaves turning brown and dying. The leaves are first turning brown at the top of the trees and then work their way down the tree with the leaves turning brown and falling off. The trees are in Tijeras Canyon at about 6200 feet elevation and are watered once a week to 3 times a week. What is wrong with our trees? Is there anything we can do to save these trees?

Cathy F.

A.

I suspect you are watering too much, at least too often. How much water do you apply with each irrigation? Oaks (especially bur oaks) are fairly tolerant of drying. If you have deep enough soil to grow oaks, you probably only need to water once every two weeks after the trees are established. When you water you should moisten the soil to a depth of 3 feet (if there is that much soil). If there is less soil, then there is a chance the water will infiltrate cracks and crevices in the rocks below providing an excellent reservoir of water for the trees. If the soil is sandy, you may need to water a little more often (every 10 days). In the winter you should only need to irrigate the trees once a month, but always apply the same amount of water (water to moisten the same depth of soil with every watering). Mulch will help conserve water and reduce the needed frequency of irrigation as well. It also helps moderate changes in soil temperatures, this is good for roots.

Watering too frequently can have several negative effects. The first is to suffocate the roots. Roots need oxygen in the spaces between the soil particles. Frequent irrigation fills those spaces with water and the roots cannot get the oxygen they need. Frequent and excess irrigation adds salts (various minerals dissolved in the water) to the soil. As these minerals accumulate, they can reach levels that cause"salt burn" in the leaves. This may be what you are seeing. To help alleviate the problem, when you irrigate, apply excess water (more than the amount needed to moisten to 3 feet) to leach the salts away from the roots, but do not irrigate more frequently.

It may not be too late to try change your watering frequency. If the roots have not been killed, they may recover. Let the soil dry between irrigations. Do not worry if the surface soil drys. Use a long screwdriver or other metal probe to see if the soil is moist several inches down between irrigations.

Marisa Y. Thompson, PhD, is the Extension Horticulture Specialist, in the Department of Extension Plant Sciences at the New Mexico State University Los Lunas Agricultural Science Center, email: desertblooms@nmsu.edu, office: 505-865-7340, ext. 113.

Links:

For more gardening information, visit the NMSU Extension Horticulture page at Desert Blooms.

Send gardening questions to Southwest Yard and Garden - Attn: Dr. Marisa Thompson at desertblooms@nmsu.edu, or at the Desert Blooms Facebook page.

Please copy your County Extension Agent and indicate your county of residence when you submit your question!