Issue: September 21st, 1998

Is is good to drain evaporative cooler in garden?


For years I have drained my evaporative cooler each fall and used the water to irrigate my garden. This year I heard that this is not a good thing to do. Can the water from my cooler be harmful to my garden?


There are several factors to consider when answering this question. First, do you use products to keep the lime scale from accumulating in the cooler? Do you use the anti-algae or anti-fungal products in your cooler water? These products may be harmful to plants. So, if the material is still active, it may cause problems. Have you seen problems with your plants when you dumped the cooler water on them? If these products are in the water and you have not seen injury to the plants, it is probably okay to use. However, not knowing the product you use and its constituents, I would advise that you dispose of the water on flowering plants, not on vegetable crops.

Another important factor to consider is the fact that as water does its job of cooling the air, it evaporates. Any dissolved minerals in the water are left behind in the cooler pan. While plants need minerals, these are in high concentration and may cause plant injury. New Mexico water usually has high concentrations of calcium. In some parts of the state, levels of sodium are fairly high. Too much of either of these can be harmful to plants. It takes less sodium to cause problems than calcium. Some plants can tolerate fairly high levels of calcium, especially those native to our arid land. There are even some plants which tolerate fairly high sodium levels, but these are often less desirable plants such as salt cedar. If you are growing plants which tolerate high levels of the minerals in your water, these plants are less likely to be damaged by the cooler water than are plants native to soils of regions with more precipitation. Plants from moist climates often prefer acid soils and do poorly in alkaline soils. Our soils are alkaline, and addition of high concentrations of minerals can make conditions worse and kill or injure these plants.

Lemons and Limes


Are limes immature lemons or an entirely separate plant?


Limes and lemons are different species in the same genus. The lime is Citrus aurantiifolia and the lemon is Citrus limon. Since they are in the same genus, Citrus, they are closely related, but since they are different species, they are really different plants.

Geranium cuttings


Can I start new plants of my geraniums by cutting a stem and putting it in a glass of water?


While it is possible to start some plants easily by placing a stem in water, other plants are more difficult to start in this manner. I have found the geranium to be one of those more difficult to start in water; however, I know people who have had success.

Succulent plants, which store water in their stems, such as the geranium, tend to rot rather than forming roots if placed into water or a potting soil which stays too wet. This does not mean that you shouldn't try rooting geraniums in water, but if you are very interested in success, you may wish to start the cuttings in a sandy, well-drained, potting soil.

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:, 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, or at the Desert Blooms Facebook.

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