How does grass grow?

Taking into consideration a healthy, watered and fertilized lawn with healthy blades of grass, I have these questions: (1) How long does a healthy blade of grass live? (2) Can old age kill the blade of grass? (3) Does something near the blade of grass re-generate into another blade of grass or do you need to re-seed? Thank you.

R. Perkins
Taos

This is an interesting question. When you are familiar with topics in your profession, you often forget that other people do not know things that you take for granted. Thanks for asking this question.

A single blade of grass does have a limited life span, much like the leaves on a tree. The length of time a single blade persists depends on several factors. Shade or lack of shade, variety of grass, moisture conditions, and season of the year are a few things that affect longevity of a blade of grass. These same factors influence the duration of leaves on a tree. I have never seen any published information about grass blade longevity. My experience indicates that some grass blades remain alive for several months. They may remain on the plant for years even after dying and turning brown.

New grass blades are produced regularly during the growing season from a "growing point" in the crown of the plant. The crown is located at the base of the existing leaves. As long as the crown of the grass remains healthy and the weather permits, new grass blades are produced.�

Some grasses are annual plants that live for one growing season then die. These must be reseeded if you wish to have them present the following growing season. Some weedy annual grasses reseed themselves. Other annual grasses, such as corn, require replanting by us. Most lawn grasses and many native grasses are perennials that return from the dormant crown as a new growing season begins. Perennials may be killed by drought, fire, or disease and require replanting. However, with proper care they will continue to grow and produce grass blades for many years without requiring replanting.

Planting in cold frame?

When can I start to plant greens and beets in my unheated cold frame? Should I start them indoors first? Thanks a lot.

Many greens (collards, mustard, kale, and others) and the beets can tolerate freezing (or near-freezing) temperatures. Do you have thermal mass inside the cold frame? This can be provided by bottles filled with water to release heat at night/absorb heat in the day. This will moderate temperature variation between day and night. Monitor the temperature inside your cold frame and when the night temperatures don't go much below freezing, you can plant. Also, monitor the soil temperature. Once the night air temperatures are moderated and the soil temperature is near 50 degrees F., the greens will germinate. In some parts of New Mexico these conditions already exist; in higher elevations and northern locations you may need to wait, depending on conditions within the cold frame.

Soil temperature will be the limiting factor. Planting greens and beets directly into the cold frame will allow them to germinate as soon as conditions are correct (especially soil temperature). Onions are another plant that can be planted now in the cold frame.

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.

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

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

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