Effects of Gray Water on Radishes

Conflicting Advice

• Conflicting advice is given concerning use of grey water on vegetable crops. According to the University of Utah, the state forbids using grey water on vegetables if there is any possibility the water will come into contact with the edible parts of any vegetable, which means you couldn't use it for radishes. The University of Washington advises not to use grey water on vegetable gardens where any of the produce is consumed by people.

Pathogens

• The Global Water Partnership acknowledges that in poorer countries, grey water may be the only available irrigation water and recommends that it not be used on vegetables that are consumed raw, which many radishes are. The primary concern with grey water is that it often carries pathogens that can transfer to the vegetables and then to humans. Radishes, which are grown in the dirt, are surrounded by the grey water, unlike vegetables such as tomatoes and peppers, which are above the soil and have a lesser chance of contamination.

Poor Growth

• Grey water is a mixture of everything that comes from the drains of a home, except those containing body wastes. Some of these, such as grease and non-biodegradable detergents, are not good for the soil. Many detergents use phosphorus as a cleansing agent, while other cleaners use ammonia. Both can quickly overload the soil with too many fertilizer salts, leading to abundant leaves and undersized radishes.

Choices

• If you supply the grey water with an underground soaker system and avoid using it with root crops such as radishes, carrots, turnips and potatoes, along with other at risk leafy vegetables such as lettuce and spinach, you might be able to use your grey water on your garden. Otherwise, it might be better to direct the water to your ornamentals, lawn and trees. Always be careful of what goes down the drain, and avoid chemicals that will do more harm than good.