HCD Newsletter for July 2007


August – September: A Time for Planting?


Well, the HCD irrigation season is half over and the heat is on. Daytime high temperatures (as recorded at NMSU’s Agricultural Science Center: http://cahe.nmsu.edu/aes/farm/weather.html#anchor_14912) have been in the mid to upper 90s during the past few weeks. The 0.79 inch of rain received at the east end of CR 5500 (West Hammond Road) last Wednesday evening http://www.cocorahs.org/ViewData/StationPrecipSummary.aspx (Enter Station NM-SJ-3) was welcome and provided a slight bit of relief (for some) from the western New Mexico drought: http://weather.nmsu.edu/drought_reports/JunStatusReportFinal.pdf.


The water-use (evapotranspiration) of a good, solid stand of alfalfa has been estimated to be about 0.35 inch per day (2.5 inches per week) over the past few weeks. A thick, healthy, cool season grass pasture should be using about 80 to 85% of this (0.29 inch per day or about 2.0 inches per week). Assuming an irrigation efficiency of 80%, nearly 12,000 gallons of water per acre per day (84,000 gallons per acre per week) would be required to satisfy the estimated water demand of a healthy, full alfalfa canopy during this time of year.


August – A Time to Plant New Alfalfa


August is the best month to plant alfalfa in San Juan County for a number of reasons (lower wind than in Spring resulting and higher irrigation efficiency and less seedling damage, soil erosion, etc., reduced weed pressure, higher humidity and more frequent rains, more stable temperatures, better root development as nights cool and days shorten, etc.) and now is the time to start preparing your field. Fertilization (high P, low N), followed by plowing or disking and a few alternating irrigations and cultivations or sprayings with glyphosate (i.e. Roundup) can provide you with a clean, weed-free seed bed for planting. Be careful not to destroy the soil’s structure, however, by over-tillage and/or compaction. To insure a good stand, plant high quality seed at a rate of about 20 pounds per acre during the first or second week in August, or, as I’ve heard some “experts” say – ‘plant and irrigate before the first pitch is thrown in the Connie Mack baseball tournament’. Keep soil moist until emergence.


New Mexico State University’s Agricultural Science Center at Farmington has evaluated the growth and yield of many different alfalfa varieties over the years. During the past few years, varieties such as Ranger, Legend, and Archer II have consistently appeared in the list of top producers but other, newer varieties have also exhibited good yield potential. For a complete list and description of alfalfa varieties that have been evaluated throughout New Mexico (including San Juan County), along with quality and yield values, go to:



For more detailed information on planting alfalfa in San Juan County, refer to the Alfalfa Production Fact-Sheet prepared by NMSU’s Cooperative Extension Office and Agricultural Science Center: http://www.sanjuanweeds.com/FactSheets/AlfalfaProdFS.pdf

An alfalfa IPM Manual from Colorado may also be useful:



Other Crops


Late summer or early fall is not only the optimum time to plant alfalfa but it’s also an ideal time of year to plant various other perennials such as cool season pasture grasses (tall fescue, orchardgrass, perennial ryegrass, meadow brome, wheatgrasses, etc.) or turf (Kentucky bluegrass, fescue varieties, etc.). Actually, because the seed of many of these grasses can germinate at cool temperatures, and these grasses thrive during cool weather, they can be planted through late September in San Juan County. Other landscape perennials, including native, xeric (drought-tolerant) species can also be planted in August or September but many must be well-established before the first hard freeze (about mid-October). For some ideas on plants suitable for water-efficient landscapes in San Juan County, see: http://cahe.nmsu.edu/aes/farm/xeriscape-plant-specimen.html.


Warm season grasses (buffalograss, blue grama, or bermudagrass, etc.), the seeds of which require very warm soil temperatures for germination, should be planted before August 1 to insure good establishment before the first frost. Three varieties of bermudagrasses that have performed well (and survived several winters) at the Agricultural Science Center include: Wrangler, Yukon, and Riviera. These varieties were developed in Oklahoma. Most other bermudagrasses were developed in hotter, southern latitudes and will winter kill in northern NM.


Fall is an excellent time to plant bulbs, shrubs, and various ornamental or fruit trees. The warm days but cooler nights stimulate rapid root growth as the new plants prepare for over-wintering. July is the month to plant vegetables that like to mature when cooler weather arrives. Cole crops (cabbage, broccoli, kale, etc.) and salad greens (lettuce, spinach) are some examples. Over-wintering crops, such as garlic, winter onions, and asparagus can also be planted in late summer or fall. For much more information on vegetable gardening in New Mexico, see: http://cahe.nmsu.edu/pubs/_circulars/circ457.html


So, while harvesting and enjoying the bounty of our spring-planted gardens is on most of our minds, don’t forget that late summer and fall is also an opportune time to plant anew. Don’t’ forget to share all those extra zucchini with your friends and neighbors.


Questions? Comments?

Email: dsmeal@nmsu.edu

















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