As the owner of a small courtyard garden in London, there is one gardening tool I recommend above all others: a potting mat. Right now, IKEA is selling a striking version for £1.50 that I'm telling houseplant parents and small garden owners alike to pick one up.
A potting mat is essentially a foldable, waterproof, plastic sheet with high sides that will contain all the mess of sowing seeds and potting up plants. When you've finished planting, you can pour leftover compost back into the bag, rinse the mat off and fold it away.
