Potash strengthens plants and makes them more weather and disease resistant. It also encourages flower formation and colour, leading to better blooms and higher fruit yields. It is particularly beneficial to tomatoes.
Apply it from early spring to November as a base dressing before sowing or planting. Sprinkle it evenly over the whole area 70g / sq m (2oz per square yard) and work it into the top 10cm (4 inches) of soil with a hoe or rake. As a top dressing to established plants, apply early in spring 35g / sq m (1oz per square yard) generally and up to 140g / sq m (4 oz per square yard) for fruit trees and bushes. Sprinkle evenly between rows of vegetables, amongst flowers and over the whole area covered by the branch spread of trees, shrubs and fruit bushes. Hoe or rake in and, if dry, water well for maximum benefit. Do not apply as a heap at the base of the stem and shake off any that lodges on the foliage. It may also be dissolved in water 40g / 10 litres (1oz in 2 gallons) and used as a liquid feed.