Issue: March 1, 2003

Rhubarb

I would like to know the correct way to fertilize rhubarb. I have not been successful in the past. Frank E.Roswell

When fertilizing rhubarb, it is important to consider the salt you are adding, as well as the salt already present in the soil. All fertilizers add salt. Rhubarb is native to soils that are moist, contain much organic matter, and little salt.

The part of the plant of interest to gardeners is the leaf petiole (the leaf blade is poisonous). Therefore, nitrogen (needed for leaf growth) is the most important nutrient to add when fertilizing. Other necessary minerals are probably present in the soil in sufficient quantities and do not need to be added, but they may be present in the fertilizer you will apply. A soil test can help you determine what nutrients should be added. Your local Cooperative Extension Service office can help you get your soil tested.

Commercial fertilizers may be a good source of nitrogen if used carefully. Do not over-apply fertilizers. Manure can also be used to supply the nitrogen, but be very cautious because manures common in New Mexico are high in salts. For gardeners who are considering growing rhubarb in New Mexico, remember that it is not native to New Mexico. It is from moist regions of the world with constant soil moisture, well-drained soils, low salt concentrations in the soil, and high organic matter concentrations. These conditions are difficult to replicate in New Mexico. That doesn't mean we can't grow rhubarb here, only that we must modify the soil and frequently replant into newly prepared soil. Gardeners who successfully grow rhubarb in New Mexico also plant in shady, protected locations. Our sunlight and wind can cause leaf burn, reducing growth of rhubarb. Gardeners also recognize that in much of the state rhubarb will grow during the cool season and become dormant in mid-summer.

A few garden "must do" items

I will be helping my son and daughter-in-law establish their garden/yard at their new home in Sandia Park. Can you suggest one or two absolutely "have to do" tasks to prepare the soil for planting (trees, shrubbery, perennials, herbs)? Susan B.

The most difficult part of your question is the limit of only 2 "have to do" tasks. There are several things I could mention, but I will try to address the most critical.

1. Prepare the soil. This means dig to aerate the soil, overcoming any compaction that occurred during construction. At this time, amendments such as organic matter and fertilizer may be added. Loosen the soil as deeply as possible. In Sandia Park, the soil may be shallow in places, so building raised beds may be part of the soil preparations. Soil depth will depend on what you plan to grow. Vegetables, herbs, flowers and such will do okay in soil 1-foot deep. Shrubs and some trees need soil 2-to-3 feet deep extending over a large area. Raised beds will be best for the vegetable/herb/flower garden.

2. Design the irrigation system. Water is a limiting factor here in the Southwest, especially in some of the East Mountain communities. Designing for water use efficiency is important. A drip irrigation system will help you stretch your limited water resource. Use of a mulch in the planted areas will also help increase water use efficiency. There are other things to do, but they will follow from these (proper plant selection, proper plant maintenance, etc.).

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!