Guide to Growing Celery
Versatile in cooking, celery is a fairly tricky vegetable to grow well and requires some effort. Novice gardeners should look for modern self-blanching varieties, which are easier to grow than trench types.
How to Grow
Celery prefers an open site with moist, rich, well-drained, slightly acid soil that has been improved with plenty of well-rotted organic matter, such as garden compost. Dig this into the soil in the season before you plan to grow.
Sow seeds (which can be slow germinating) under cover in early spring into modules or small pots. The seeds need light to germinate, so cover very lightly with compost, if at all. Keep the sown seeds at 60°F (15°C), then transfer seedlings into larger pots once they are large enough to handle. Grow them under cover at a temperature of 50°F (10°C) until all risk of frost has passed, then harden off and plant outside in the early summer.
Plant self-blanching varieties 9 inches (23cm) apart in blocks and trench celery 12–18 inches (30–45 cm) apart in a prepared trench. Water in well, keep the area free of weeds, and feed once every two weeks with a balanced liquid fertilizer throughout the growing season. Harvest celery after 4–8 months when the heads are big enough to use. Trench celery is the hardiest and can be left in the ground for winter; self-blanching must be pulled before the first frost.
Consider these varieties of celery for your garden: Types of trench celery include ‘Blush’, ‘Ideal’, ‘Giant Pink’, ‘Giant Red’, ‘Martine’ and ‘Pascal’; Types of self-blanching celery include ‘Crystal’, ‘Green Utah’, ‘Ivory Tower’ ‘Loretta’, ‘Tango’ and ‘Victoria'.
Traditional trench celery needs to be covered to produce crisp, tender blanched stems. Dig a trench 12 inches (30 cm) deep by 18 inches (45 cm) wide, and spread well-rotted organic matter in the bottom, topped with soil. Space plants 6 inches (15 cm) apart in the trench. When they reach 12 inches (30 cm) high, wrap the stems with cardboard to keep the soil out, and earth up against the sides. Do this two or three more times in summer, so only the leaves remain visible at harvest time. Alternatively, plant new self-blanching varieties, which, when planted in blocks, create enough shade to blanch the stems.
Watch Out for Pests and Diseases
Celery leaf miner maggots can burrow into the plants' leaves, causing dried-out areas and making the stems taste bitter. There is no chemical control, but you should pick off infested leaves.
Fungal leaf spots are another problem that can plague celery crops, causing gray or brown spots on the leaves. These spots may join up to cover large areas and, therefore, weaken plants. Pull off infected leaves, and clear away plant debris.