If you love your garden but need advice on how to keep it looking lush and welcoming all year round, top head gardener Tom Brown can help. In this regular column he demystifies common gardening problems, explains what to tackle when, and shows how to make every moment on the plot more fun and productive. Happy gardening!  

Dear Tom, 

How can I grow an avocado from seed?

Avocado trees are native to Mexico and Central America, and grow in warm, humid environments. In the UK, it is possible to grow avocados from seed, starting with a supermarket fruit, but do be aware of the conditions that they need to grow happily.

A few sheltered places, especially in cities, offer microclimates that can support an avocado tree outside, but for the majority of us, they make fun, tropical houseplants that will last a few years before starting the process all over again.

So, to grow a plant, carefully extract the seed from the fruit. You now need to decide whether to grow the seed hydroponically (in water) or traditionally, in soil. Both methods require the flatter, broader end of the seed to point down, as this is where roots will emerge long before any shoots.

To start off your avocado hydroponically, half-submerge the seed in a glass or jar of water. To suspend the seed, insert three toothpicks or cocktail sticks horizontally about three quarters of the way up the seed to form supports. Avoid any small cracks which may open when pierced. Then sit the seed over a container of water so that the water comes halfway up its sides.

To grow an avocado in a pot, slightly bury the seed in a pot of peat-free compost. A sunny windowsill and a large, clear plastic bag over the pot will help retain moisture – young avocados do not like to dry out. Avocados in water need regular water changes to prevent rot but the joy of hydroponic growing is to see the roots developing, which can be fascinating. However, there is a trade-off when it comes to potting the plant into compost – the transition can take its toll on the avocado and stop growth, meaning that seeds started off in soil often catch up and overtake those grown in water. Soil-grown avocados can take months before you see any results so you’ll be tending a pot of compost for some time. If you need instant gratification, enjoy growing your avocado hydroponically.