Sometimes in the veg garden, something goes spectacularly right - a truss of unblemished tomatoes, or a huge marrow. Entering your best produce to a show is a good way of finding out how good it really is.
Discover the best vegetable plants for beginners.
Grow more veg than you need to allow a few plants to fail and to give you a good selection to choose from - you'll need several of the same shape and size.
We talked to prize-winning grower Medwyn Williams, who has 11 Chelsea gold medals and an MBE for his flawless exhibits, for his tips on growing crops that will impress the judges.
What judges want: Good weight and girth, freshly cut, no cracks or pest damage
Top variety: 'Atlantic Giant'
How to grow: Medwyn's son grows two or three pumpkin plants in a 30m polytunnel and bury each leaf joint, encouraging a huge root system. Failing that, give plants warmth, very rich soil, and lots of extra feeding.
What judges want: Straight roots with a well-rounded stump end, no cracks or greening
Top variety: 'New Red Intermediate'
How to grow: Medwyn grows carrots in 45-gallon drums filled with sand. Alternatively, make beds of damp sand 60cm deep, then twist out 40cm deep cores. 7.5cm in diameter. Fill each hole with compost and sow three seeds on top, thinning to the strongest. Cover with insect-proof mesh to keep out carrot fly.
What judges want: Uniform size, firm texture, even colouring, blemish-free with a bright green calyx
Top varieties: 'Shirley', 'Myriade' and 'Goldstar'
How to grow: Grow in a cool, well-ventilated greenhouse. Medwyn waters just-planted seedlings with a pint of water, then leaves for 10 days, to make the roots go deep to search out water. He then gives them a good soak and keep them moist from then on.
What judges want: Deep green colour, uniform length and no strings - the judges will snap one to check
Top variety: 'Stenner'
How to do it: Runner beans need rich soil and strong supports. A few days before, looks for straight, flat beans, 35-40cm long. Stand them in water, stalk down, then the next day go back for more, so that by show morning you have a set of identical beans.
What judges want: A uniform shape and size, with a firm texture and well-ripened, unblemished, dry skin
Top variety: 'Kelsae'
How to do it: Start early. Medwyn sows onion seeds into heated propagators, then moves them outside in mid-May, planting throught black and white polythene, laid white side up to reflect heat onto the bulbs. Lift the bulbs three weeks before show day to dry.
What judges want: Uniformity of size, colour and shape, with no yellowing or soil splash marks
Top variety: 'Table Dainty'
How to do it: Even colouring can be tricky, as marrows on the ground usually turn yellow beneath. Medwyn trains his up a framework. Alternatively, put each fruit on glass raised up on two bricks, so light can reach the underside. Give marrows rich soil and lots of feeding and warmth.
What judges want: Straight, with an equal ratio of leaves to shank. A perfect V where the leaves wrap round the barrel.Top variety: 'Windermere'
How to do it: Exhibition growers raise leeks from 'pips' formed on their best plants from the previous year. In September, trim your best leek's roots and cut the top down to 15cm. When it flowers in spring, snip off every bloom. It will produce grass-like baby leeks from the seedhead - gently remove and pot up for this year's champions.
What judges want: Tubers of identical size and shape, with unmarked skin, shallow eyes and no signs of scab
Top variety: 'Mona Lisa'
What judges want: Evenly coloured pods, with an unblemished bloom, well filled with 6-15 peas.
Top variety: 'Show Perfection'
What judges want: Smooth skin with no scabs or splits, and a single, intact tap root
How to do it: Sow seeds in deep, well-turned soil and thin to 5cm apart. As they grow, earth them up to cover the globe so the skins don't turn corky on top. On show day, keep the skins moist by covering with damp kitchen paper until the judges come round. Damp skin has that fresh, just-pulled look and it helps soften scuff marks.
Top variety: 'Pablo'
What judges want: Straight, fresh fruits, a short 'handle' (the thinner, stalk end) and an untarnished, natural bloom.
Top variety: 'Carmen'