Mustard is a fast growing green manure that can be sown from March – September. It has a growing period of 1-2 months and can reach 60-90cm tall. This half-hardy annual grows on most soil types but particularly likes fertile ones. It may require additional watering in dry periods especially to help it establish.
Mustard produces large volumes of green matter and residual fibre which when chopped up and dug in is particularly good for soil that lacks organic matter as it helps to improve soil texture and moisture retention. It is not very hardy but may come through a milder winter. If it does get frosted, the foliage can be left on the soil surface as a mulch. It will gradually be incorporated by worms etc. and the remainder can be dug in during early spring.
After 4-8 weeks of growth chop down the plants and cultivate into the top few inches of your soil. On sandy ground let mustard reach 40cm in height before digging in. This will produce more fibrous plant matter that can help very free draining soils retain more moisture and nutrients.
It is also thought that mustard may reduce the population of wireworms by stimulating the pest to complete their life cycle much quicker - these insects can devastate a crop of potatoes. (We sow it before planting our seed potato beds).
It is part of the brassica family so caution is needed if sown before a brassica in a crop rotation plan as it may increase the likelihood of diseases.
The seeds produced are used to make the yellow mustard sauce that Americans use on their hotdogs. This green manure is not suitable for human consumption.
