Gardeners rely on knowledge and techniques specific to place. New Mexico gardens are located at significant elevation, in dry air, on mountain soils and soils that formed in an arid environment. We experience strong variations in temperature and moisture conditions among locations, seasons and times of day. The Cooperative Extension Service at New Mexico State University offers advice, expertise and research in gardening methods for our unique environment.
A wealth of resources about New Mexico gardening (including those listed in this booklet) can be found at: aces.nmsu.edu/pubs
Texture of Soil
New Mexico soils may be heavy or light and are often lacking in organic matter. Most plants will benefit if you add organic matter (e.g., manures, leaf mold, sawdust, straw) to your soil. These organic materials will be decomposed by soil organisms including beneficial bacteria, fungi, worms and insects.
Keep in mind that soil organisms require nitrogen for their metabolism and structure. Depending on what kind of organic matter you use, you may need to add nitrogen as well.
- Dry, undecomposed substances such as straw, leaves or dry mulch will require the addition of nitrogen.
- Fresh green wastes will contain sufficient nitrogen for decomposition.
A soil test will help to tell you what sort of fertilizer will be appropriate for your garden. Fertilizers sold as plant nutrients have three numbers on the bag.
- The first is percent by weight of nitrogen (N).
- The second is percent by weight of phosphorus (P).
- The third is percent by weight of potassium (K).
If other nutrients are guaranteed to be in the fertilizer, then the N-P-K numbers are followed by the percent by weight of other nutrients. Soil type, plant type, the amount of water and nitrogen applied and other factors also affect the amount of fertilizer you need to apply.
Cover crops (green manures) can also be used for soil improvement. Legume cover crops reduce synthetic fertilizer needs, and deep-rooted cover crops can help break up a hardpan and improve tilth. Plant them in the garden in fall; incorporate into the soil in spring. Sow seed for your cover crop a little before the first killing frost. If you are growing a fall garden, plant cover crops between the rows and in any cleared areas. Cover crops should not be allowed to go to seed.
Common cover crops include
- Annual rye
- Perennial ryegrass
- "Elbon" cereal ryegrass
- Hairy vetch
Before beginning a garden project, it's a good idea to measure your soil pH, which affects the availability of various nutrients. Neutral or slightly acidic pH (6-7) is ideal for most plants but is rare in New Mexico. Soil testing can help you decide what amendments to add to adjust pH and nutrient levels for good plant growth. Most New Mexico soils are high in alkalinity; therefore, amendments such as elemental sulfur or aluminum sulfate are needed to adjust pH and reduce alkalinity. Many ornamental plants require slightly to strongly acidic soil.
Mulch provides a cover over the soil, reducing evaporation and erosion and moderating soil temperature. It also limits weed growth and competition for water and nutrients. It is a good idea to mulch gardens and landscaping plants with 2 to 4 inches of organic material twice a year.
Common materials for mulching include shredded pine bark and compost, but many organic substances can serve as mulch, and inorganic (e.g., rock) mulches are sometimes used. After it decomposes, organic mulch can be incorporated into the garden soil.
One way to think about irrigation is that the soil is a bank account of water for plants. A proper irrigation schedule refills the bank account of water and keeps the account at acceptable levels for the plant to withdraw.
Some irrigation is necessary for most New Mexico garden landscapes, including xeriscapes (landscapes using water-efficient plants).
Water should be applied as efficiently as possible. Sprinkler systems are appropriate for areas of turf, but drip, bubbler and microspray systems or soaker hoses are more appropriate for shrubs, trees and annual or perennial plantings. Efficient irrigation applies water only when and where it is needed, not where it will be wasted and benefit only weeds.
Techniques for Water Conservation
Choose plants with low water requirements, which frequently are adapted to the alkaline soils characteristic of New Mexico and other dry regions. These xeric plants depend on the formation of extensive root systems to effectively gather water for proper growth. While they may look unimpressive in nursery containers, they rapidly become beautiful plants in the landscape.
Hydrozoning involves designing the landscape with areas for plants with differing water demands. An example would be locating higher water use plants together in an oasis where people spend more time, such as the patio area or entry area.
Use "found water" or "harvested water" that runs off roofs and paving during storms. This can be directed to the oasis or other areas, reducing the need for supplemental irrigation. Water harvesting may require grading to channel and detain runoff; this should be planned during the design phase of the landscape.
Mulching provides a cover over the soil, reducing evaporation, soil temperature and erosion. It also limits weed growth and competition for water and nutrients.
Appropriate turf provides a play surface for children and pets and is an important element in cooling the local environment, reducing erosion and preventing glare from the sun. In choosing an appropriate turfgrass species, consider where and how large a turf area is desired, how it will be used and during which seasons it will be used.
Maintaining Turf (Lawns)
If the use is light or mostly in the warmer months and in southern New Mexico, use a grass that needs less water, such as buffalograss, blue grama or bermudagrass. If the area is only for appearance, other ground cover may be more appropriate and may be irrigated more efficiently. Choose the best plants by carefully defining your needs and purposes before selecting plant species.
In Northern New Mexico and higher elevations of the state, cool-season grasses are best for areas used extensively as play areas, especially if this use extends into the early spring and late fall. Fescue or a fescue-bluegrass mixture is appropriate for these areas.
Managing Plant Problems
Preventive weed management (keeping weeds out) is often the most effective technique. Preventive weed management means
- planting certified seed
- cleaning along fence rows and ditches
- making sure not to bring in soil infested with weed seeds
Cultural weed management means allowing your preferred plants to be more competitive by managing the other components of the lawn or garden. Management priorities include
- irrigating correctly
- managing fertility (timing and type of fertilizer depending upon plant species)
- mowing to the correct height (depending upon turf species)
- managing potential diseases and insect problems
Mechanical weed management means physical removal of weeds. This works better for annual weeds; it may actually help to propagate perennial weeds by distributing root parts from which perennials reproduce.
Chemical weed management means use of herbicides.
Weeds are divided by lifecycle into the following groups: annual, biennial and perennial.
Annual weeds only spread and reproduce by forming and dispersing seed. This makes for a simple management principle: Don't let them set seed. However, any management plan must deal with multiple germinations, because these weeds will germinate in the soil whenever conditions are favorable. Once you have dealt with the first flush of annual weeds, another group of seeds will be waiting in the wings for their chance to germinate.
Biennial weeds take two years to complete their life cycle – otherwise they act like annual weeds (spreading by seed).
Perennial weeds return year after year from roots and often reproduce from underground rhizomes, though they may also reproduce from seed.
Plant disorders (abnormal plant growth) may be caused by infectious microorganisms (pathogens/diseases) such as fungi, bacteria, viruses, phytoplasmas, nematodes and parasitic plants, or by non-infectious entities (abiotic) such as poor soils, pesticide toxicity, air pollution, strong winds, hail, improper cultural practices or extremes of temperature, moisture, light or nutrients.
Plant Disease Control
- Take advantage of resistance or tolerance: Choose varieties that are tolerant to pathogens common in your area.
- Cultural control: Take care of plants; strong-growing, vigorous plants have better defenses against disease.
- Biological control: Beneficial microorganisms will help to manage pathogens.
- Chemical control: Fungicides are toxic to the organisms that cause pathogens.
A disease episode requires the interaction of three components: the host, the pathogen and the environment. Successful disease management requires the disruption of some part of the disease triangle.
An example of targeting the host would be preventing the plant from becoming stressed by making sure it has enough water and nutrients.
An example of targeting the pathogen would be using preventive fungicides.
An example of targeting the environment would be choosing a planting date to avoid extreme temperatures or moisture conditions.
Steps for diagnosing plant diseases
- Identify the plant species.
- Observe the symptoms of the problem.
- Take accurate information about growing conditions (soil type, quality and drainage; plant's location; sun exposure; proximity to buildings, roads or walls).
- Collect a sample. Collect the whole plant if possible. Otherwise, choose material between diseased and healthy tissue. Keep the sample cool, wrap in dry newspapers or paper towels (do not seal in plastic) and promptly contact your county Extension office for advice or send to the NMSU Plant Diagnostic Clinic, plantclinic.nmsu.edu (see full instructions in NMSU Extension Guide H-158: How to Collect and Send Plant Specimens for Disease Diagnosis).
Contact your county Extension office:
Visit our NMSU gardening website:
Kerry Bowers, Ryan Goss, Ana Henke, Norm Lownds, Jesse Ramirez, Curtis Smith, Geraint Smith, Stephanie Smith
The text of this booklet was adapted from the NMSU Master Gardener Manual, edited by Curtis Smith, Extension horticulture specialist.
Guide A-114: Test Your Soil
Guide A-129: Nitrogen Fixation by Legumes
Guide A-229: Phymatotrichum Root Rot
Guide A-231: Blossom-End Rot
Guide A-615: Dodder (Cuscuta spp.) Biology and Management
Guide H-106: Curly Top Virus
Guide H-108: Choosing Organic Matter for the Home Garden
Guide H-110: Backyard Composting
Guide H-119: Determining Amounts of Fertilizer for Small Areas
Guide H-122: Yard Waste Management
Guide H-158: How to Collect and Send Plant Specimens for Disease Diagnosis
Guide H-164: Vermicomposting
Guide H-317: Apple Disease Control
Guide H-505: Mowing Your Lawn
Guide H-507: Lawn Care for Disease Control
Guide H-508: Turfgrasses for New Mexico
Guide H-707: Landscape Water Conservation: Principles of Xeriscape
Cooperative Extension Service
College of Agricultural, Consumer and Environmental Sciences
New Mexico State University
P.O. Box 30003
Las Cruces, NM 88003-8003
To find more resources for your business, home, or family, visit the College of Agriculture and Home Economics on the World Wide Web at aces.nmsu.edu.
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