Super, sensational celery! It’s a bit of a staple in my garden because it’s so incredibly useful. I like it chopped into salads and stir-fries, of course – but it’s also the starting point to soups, many curries or simply braised in stews and casseroles. You can’t help but love it! Celery isn’t difficult to grow and will potentially keep you in crisp, crunchy stems for months at a time. So here’s our Sowing to Harvest guide to celery...
Types of Celery
There are two types of celery. Trenching celery needs soil mounded up against the stems as they grow to produce crisp, pale stems. To make this easier trenching celery is typically planted into trenches, hence the name, but some gardeners aid this blanching process using cardboard tubes, pipes or collars.
The alternative is to grow self-blanching celery, which requires none of these extra steps. This makes it a lot easier to grow, and the stems are just as tasty!
How to Sow Celery
Sow celery under cover from early spring. The seeds are tiny, so you’ll need to sow with care and a keen eye. Start by filling pots or seed flats with a good-quality seed starting mix then gently firm it level. The easiest way to sow the seeds is to carefully tap the packet above the surface of the potting mix and watch carefully as the seeds fall. Ideally you want them to fall about an inch (2cm) apart. Once you’re done, firm the seeds into place.
The seeds need light to germinate, so cover them with just the very finest layer of compost or vermiculite. This will help to trap moisture around the seeds to prevent them from drying out. Water from below then remove pots once you can see moisture at the top.
Celery seeds need gentle warmth to germinate. If it’s still cold you can pop them into a propagator set to about 60ºF (15ºC), though an indoor windowsill works just fine. Germination is slow and can take up to three weeks, so you’ll need to be patient. Once they’re big enough to handle transplant them into plug trays or, to buy you a little more time, move them into their own pots.
How to Plant Celery
Celery loves a nutritious soil that has been enriched with plenty of compost or well-rotted manure. Wild celery grows in boggy ground, so you’ll need to ensure consistent moisture for this thirsty vegetable, while a sunny spot should ensure good, even growth.
Begin acclimatizing celery to the outdoors two weeks before planting. To do this, simply leave your plants outside for progressively longer each day, taking care to bring them back under cover if frost threatens. Plant them after your last expected frost date. This is important, because a sudden cold snap can encourage plants to bolt (flower prematurely) before they’re ready to harvest. If you’ve missed the window for sowing, you can often find ready-to-plant celery in garden centres.
Self-blanching types can be planted in a block about nine inches (23cm) apart in both directions. Planting fairly close together like this will create a lot of shade between them and help the stems to blanch. To plant trenching varieties the trenches would need to be just over a foot (30cm) apart, and around a foot (30cm) deep.
Once they’re planted your most important task is to keep celery well-watered at all times, which will reduce the risk of plants bolting or stems turning stringy. Add a nutrient-rich organic fertiliser as plants are establishing to help to give them a boost. Comfrey pellets are great, as are coffee grounds, tickled into the soil between plants. You could also lay a mulch of organic matter such as compost between your plants. This will keep the roots cool, help to feed your plants, and lock in that all-important soil moisture.
Start earthing up trenching varieties once the stems reach about a foot (30cm) tall, banking the soil up by about three inches (8cm) each time until you can earth up no more.
Celery is pretty trouble-free but watch out for slugs early on. Beer traps will tempt slugs away from young plants and the unfortunate victims can be disposed of as necessary.
How to Harvest Celery
Harvest celery from summer and through the autumn until the first hard frosts stop growth. In milder areas celery may overwinter, producing occasional stems throughout the coldest months then picking up again in spring before finally stretching to flower. You can harvest plants whole but cutting or picking individual stems as required will keep plants producing over a longer period.