During the cold winter weather, there is not much gardening to do outside. But for those with houseplants, we will take a look at the importance of water, as a variety of water quality factors should be considered.

Water plays a role in transporting nutrients from the soil up through the roots to the plant foliage. Water is also responsible for a plant’s ability to remain erect, as without water, plant cells will not retain turgid, will shrink and cause wilting to occur. The tiny stomata or “pores” of the foliage that open and close to allow the plant to breath or transpire will seal shut when wilting occurs.

Some indoor foliage plants are more sensitive than others to lack of water, as they quickly wilt and may not recover. The permanent wilting point is when a plant reaches the stage of wilting from which it cannot recover as permanent cell damage has occurred due to lack of moisture. Fortunately, there are many houseplants that are more wilt tolerant and will recover.

Leaf yellowing, tip browning, and leaf drop are symptoms that indicate a lack of moisture. These same symptoms may also indicate use of chemicals in the water supply. City water is filtered and treated with chlorine or other disinfectants to help eliminate harmful microorganisms to ensure a safe water supply. However, these chemicals may affect sensitive houseplants, but chlorine rarely causes trouble in tap water used for plants, is that while moving through the municipal system, most of it volatilizes. To be on the safe side, let tap water stand overnight before using.

Use of a water softener adds salt to your tap water and the soluble salts can build up in the soil reducing nutrient uptake. Houseplants vary in sensitivity to salt, which can cause stunted growth, browning of leaf edges and wilting. Frequent leaching or running water through the pot can help to reduce salt buildup in the soil. Do not allow plants to reabsorb this water, as it contains salts and minerals that can be toxic when they’re concentrated in the soil.

Excess watering can also cause a plant to wilt, as water-logged soil lacks air space for plants to breath, so the plant wilts and roots begin to rot. Repotting in fresh, dry soil may help to save a plant that has received excess water.

Did you know? Houseplants benefit from an occasional cleaning. Dust settles on leaves and clogs the stomata. Dust hinders light absorption as well as gas and moisture exchange. Give your houseplants a lukewarm shower to wash the leaves. Allow water to run through the soil, which helps to leach out salt and mineral build-up.

Horticulture Questions? Contact McCormick at yvonne@iastate.edu for information or advice.