Gardening 101: Preventing plant stress in times of change
Often when we buy plants, we have a specific position in mind for them within our home or garden. But what happens when that changes? Perhaps the plant would look better in a different position or room and needs to be moved. Conditions around the plant, such as temperature, light and humidity, may also alter - particularly at the start of a new season. Maybe you’re moving house and need to transplant special plants from the old garden to the new, or move them from house to house. Plants are creatures of habit, and if the conditions are not exactly the same in the new location, this can cause plant stress.
Conditions can also change without any action on your part. A tree or structure may come down, opening a patch of garden or a sheltered window to full sun. The reverse can also occur, where a sunny spot becomes overshadowed by a new building or neighbouring plant growth. Other plant stresses can also come about with changes in season and the weather. A sudden hot spell or an unexpected blast of cold when it should be warm can also affect plants adversely.
One indoor plant that can be affected adversely by a change of location is weeping fig (Ficus benjamina and species). A move and a change in light levels can cause this plant to drop its leaves entirely, before growing new leaves better suited to the new light conditions. Good care will encourage the plant to recover and resume normal growth.
Preventing plant stress
There are several ways to help your plants cope with change. You can protect them by introducing changes gradually, by using physical barriers such as shade screens, or by applying health tonics and anti-transpirants. Plants that are well watered and cared for will also be better able to withstand stressful times.
Plant stress prevention method 1: gradual change
When consciously moving plants into a new situation, do it gradually and in small increments. For example, if you have to move an indoor plant into a more brightly lit spot such as outside, bridge the gap by putting it into a shaded position outdoors first. Turning potted plants so that all sides get the best light conditions over several months also helps to combat stress.
Plants propagated from seed or cutting should also be gradually exposed to outside conditions. For example, move the plants from your propagating area into more light, but don’t put them straight into the garden or into full sun. This gradual exposure to new conditions is called ‘hardening off’ and allows the leaf cells in the plant to adjust to their new environment slowly, or new plantings to expand their root system so they can take up more moisture from the soil to cope with high rates of transpiration in brighter light.
Plant stress prevention method 2: physical barriers
Use physical barriers in tandem with hardening off, or to mitigate the effects of a sudden change. For example, a plant that’s used to shade and shelter will need a temporary screen of shade cloth or cardboard if it has to go into a more brightly lit spot or into full sun. Indoors, use a lightweight curtain to reduce the full impact of the sun on a hot window, or tape bubble wrap over the glass to reduce exposure to cold. Physical barriers can also protect plants from unexpected changes such as a sudden heatwave or a frost. Use the same techniques for temporary protection. Signs that a plant isn’t coping with its new position include leaves browning or dropping through being burnt (either by too much heat or too much cold), or wilting as they are unable to take up moisture quickly enough.
Plant stress prevention method 3: stress-free products
Various tonics and anti-transpirant products are available to shield plants from stress. Tonics – such as seaweed-based liquids (for example Amgrow Seaweed Concentrate and Seasol) – help plants cope with stress by strengthening cells, improving micro-organisms in the soil and encouraging strong root growth. Apply seaweed tonics to stressed plants and at transplanting following the instructions on the container.
Anti-transpirants create a shield over leaves to help protect them from losing too much moisture and can also protect against frost. Products such as Yates Waterwise Drought Shield create a polymer film over foliage that helps to reduce transplant shock. Apply before hot weather or the first frost for best protection following instructions on the container. The film grows with the plant, but you'll need to reapply every 3 months or so.