Coffee grounds in compost
Useful in moderation, mixed with other compost ingredients.
Evidence: Practical extension guidanceGarden & plants
Category
Garden & plants
Compost heaps, seedlings and garden beliefs put to the test.
9 prepared entries
Eggshell barriers against slugs
A garden favourite that failed to reduce damage in an RHS trial.
Evidence: Not supported in an RHS trialGarden & plants
Epsom salts for tomatoes
A garden myth: extension advice says it leads to more blossom end rot.
Evidence: University extension says it can make blossom end rot worseAvoid this useGarden & plants
Dishwashing liquid for aphids
Soap sprays work on soft-bodied pests, but homemade mixes can harm plants.
Evidence: University extension: works on soft-bodied pests; plant injury possibleImportant limitationGarden & plants
Cinnamon on seedlings
Popular for damping off, but untested in the way gardeners use it.
Evidence: No studies matching garden use foundGarden & plants
Newspaper and cardboard as a weed barrier
Sheet mulching is an extension-recommended way to smother weeds.
Evidence: University extension guidanceGarden & plants
Willow water for rooting cuttings
Widely shared, little controlled evidence.
Evidence: Mostly anecdotal; one comparison favoured commercial rooting gelGarden & plants
Wood ash in the garden
Useful in moderation on acid soils; harmful for acid-loving plants.
Evidence: University extension guidance; test soil firstGarden & plants
Vinegar as a weedkiller
Horticultural vinegar is far stronger than household vinegar and needs care.
Evidence: University extension: strong vinegar is hazardousImportant limitationGarden & plants