Grape Cultivation and Care in Northern New Mexico
Location and Selection
Two types of grapes grow well in New Mexico. American grapes are extremely hardy. They tend to have a tougher skin and almost all are seeded. Examples of some American varieties are ‘Concord,' ‘Fredonia', ’Niagara’, ‘Canadice Red’ and ‘Himrod’.
European grapes provide most of the seedless and wine varieties. They are not quite as cold hardy as American grapes and can be damaged by an especially cold winter. Examples of European varieties are ‘Thompson Seedless',’Baco Noir’, and ‘Cabernet Sauvignon’.
Planting
Dig a hole twice as wide and only as deep as the rootball of the plant. Be sure to adjust the hole so that the top of the rootball is level to the ground level. Next remove the container. Plastic pots can be removed by turning the plant upside down or laying it on it’s side and gently tapping on the pot until the plant slides out. If it is noticed that the root ball is tightly overdeveloped, then make vertical cuts with sharp shears or a knife, 1” deep from the top to the bottom of the root ball on all 4 sides. Also, make a horizontal cut 2” deep on the bottom of the root ball from side to side and spread the cut open when planting. This procedure does not hurt the plant and will ensure proper rooting into the ground. Place the plant in the hole and refill around it’s rootball with a blended mixture of 1/3 organic compost or peat moss and 2/3 of your soil. Firm the backfill by tamping it gently.
Build a watering basin around the plant high enough to hold 3” to 4” of water. Make the basin at least as wide as the hole that was dug. Place mulch in the basin, 2” to 3” deep, using organic compost or bark. Immediately water the plant deeply by filling the basin with water once, letting it soak in and then filling it up a second time. The use of a root stimulator at planting time will greatly reduce transplant shock and encourage your plants to resume their normal growing habits more quickly.
Pruning
Grapes should be pruned each year to help control the size of the plant and to produce abundant, quality fruit. There are two ways to prune grapes: spur pruning and cane pruning. Spur pruning is the easiest to do and therefore the preferred method. However, certain varieties will not bear any fruit if spur pruned and must be cane pruned. Check your variety to see which method it requires.
Watering
Always observe local watering ordinances.
It is impossible to give a watering schedule that will be right for everyone all of the time. Such factors as soil type, root ball and plant size, how fast the plant is growing, air temperature, humidity, wind and light intensity will all affect how often a particular plant needs watering.
The basic rule of thumb is to water deeply, but infrequently. Get the water down a minimum of 18” at each watering. This encourages the plant to develop a deep, drought tolerant root system. Then give the soil a chance to dry slightly between waterings. It is common for people to kill or unnecessarily stress their plants by watering too frequently. The roots of a plant require oxygen in order to function. If the soil is constantly waterlogged, there is not enough oxygen available to the root system and the roots suffocate and die.
Knowing this, our recommendation is to maintain water basins around plants (except those watered by drip systems). The basin should be wide enough to accommodate the root system of the plant for the first 3-4 years (generally out to the drip-line of the plant) and high enough to hold 3” to 4” of water. Fill the basin full, let it soak in, then fill again. Afterwards, let the soil dry slightly (to a depth of 2” to 4”) before watering again. To determine dryness, remove a handful of soil from that depth and squeeze it; if it holds its shape then the soil is still wet; if it falls apart then it is time to water. After using this trick several times you will learn the plant’s watering schedule.
For plants that will be watered by drip or sprinkler systems, water as described above at planting time, then, within a few weeks, remove the basin. Most of the plant’s needs can now be met with your watering system’s schedule. However, a deep soaking every month or two is recommended for optimum nurturing. In addition, during the winter months, we recommend a deep soaking on a monthly basis for at least the first two years after planting.
Feeding
Begin fertilizing the spring after planting, in late April or May with granular or liquid fertilizers. Grapes prefer a low nitrogen fertilizer like ‘Gro Power’. High nitrogen fertilizers will result in fast vine growth with little or no fruit. We recommend that you maintain a mulch around your plantings at all times, 2” to 3” thick, using organic compost or bark. Mineral supplements, in addition, like Ironite, greensand/rock dust, Copperas or soil sulfur are necessary 1-3 times per year to keep soil loosened and neutralized as well as the plants properly fed.
Pests
Disease and insect problems should be dealt with as soon as they appear. Because of the variety of possible problems, proper diagnosis is very important. Bring in an affected plant sample to us so we can diagnose the problem and prescribe the best treatment available. An application of dormant spray (insect or disease) in the late winter or early spring can help prevent many problems in the coming growing season as can good sanitation in your landscape.