British Cactus and Succulent Society

Highlands & Islands Branch

Plant Management




When - how often - how much - these are the questions.

'When' is best answered by watering when the compost is dry, but not bone-dry - then water copiously. That procedure imitates nature whereas a little water now and then does not. Most growers cease watering about mid-October and plants remain dry over winter until growth re-starts about April.

In the Spring when watering resumes, there may be a problem of the compost having dried out - even gone hard. Some growers use a very small amount of 'wetting agent' (a mild washing soap) for the first and maybe second watering. Another question is whether rain water or tap water is used. One argument against rain water is that its purity is uncertain, whereas tap water is known to be clean. However, rain water is natural, although may contain significant amounts of carbonic acid, and/or sulphuric acid. Tap water can contain lime which will accumulate in pots. In summer, watering is usually done in the evening and a fine misting may be beneficial.

Water condition can affect a compost. Most waters are satisfactory as suggested above, but hard water can cause compost to cake to the extent that it becomes almost solid. A normal compost should be friable and easily break up when handled. When there is no choice on hard water, an old remedy was to add a pinch of Epsom Salts (magnesium sulphate). Some plants, especially pot-grown ones, seem to become pot-bound when a hard mat of roots develop near the surface. Water may not be able to penetrate and just runs off. The remedy is to cut away that mat, ruthlessly, and the plant will recover in most cases, if it is done when the plant is coming out of dormancy. Perhaps knowing that orchid growers often break up a pot-bound plant by hammering the roots quite hard with a mallet, and then chopping almost all the roots away with a scissors to the extent that the base of the plant looks quite bald!! The plants always recovered.

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