Celery loves water. I know because, when I was twelve years old, I absentmindedly left the garden tap turned on overnight and flooded the vegetable bed. The celery copped the brunt of it and, as a result, my stepfather swore it was the fattest, crispest, most flavoursome celery he'd ever grown! Besides which, every experienced gardener will tell you the same thing – celery does not like to dry out – never ever ever! If it does, it becomes tough, bitter, stringy, and can also (ironically)split at the seams. Consequently, I advise gardeners to steer clear of garden centre celery seedlings for the simply fact that you can't tell what drought-like conditions they've been subjected to in their short lives. If you must purchase seedlings, at least make sure they're not root bound (which would suggest they've been sitting around for too long in their punnets). So partial is celery to moist conditions, that I grow mine in a slight depression (allowing moisture to pool when it rains or the sprinkler is turned on). I add a thick layer of mulch around the plants to keep in the dampness, and sprinkle heavily with slug bait – slugs and snails revel in moist conditions, and celery is a special treat for them.
Celery is also a gross feeder- think of it as an ever-hungry teenager and you'll get the picture. As well as the usual blood and bone, seaweed, compost, and donkey pooh, I also work into the soil a good measure of well rotted high nitrogen manure such as sheep or goat pooh. To revert to imagery again, imagine you're trying to work as much butter as you possibly can into a measure of flour in order to create the richest pastry ever, and you'll understand how to apply animal manure to the soil in order to satisfy celery.
If it's all sounding too hard, concentrate on what you'll be getting in return – not only mild, fresh stems that can be served raw in a salad, stuffed with blue-vein cheese, or braised in butter, but flavoursome leaves to chop into salads and soups. The alternative is sourcing supermarket celery (never the freshest) and having to forgo the leaves which market gardeners feel obliged to hack off before delivering to their buyer.
But for those who really don't feel they have the time to devote to growing good celery, a sensible alternative is Parcel, a vigorous, tasty, easy-to-grow herb which, as its name suggests, is a cross between parsley and celery. Mine grows happily, even in cooler temperatures, and willingly goes to seed which means that I am never without it through the warmer months. Though it won't give you the thick crisp stems of real celery, it packs a punch where flavour is concerned and can be chopped and frozen for winter use when (in the far south, anyway) it tends to die down.
Tips for raising celery seed
Don't be afraid to raise your own celery seedlings. Attention to detail and a degree of patience is all that is required. Just like the plant, celery seed does not like to dry out. It's frighteningly tiny so sow it onto moist, finely sieved seed-raising mix of the highest quality, sieve over the merest hint of a covering, spray with water, and cover and seal with kitchen cling wrap. Spray again before the seed raising mix has time to dry out, and keep the container in a warm place such as a hot water cupboard, heat pad, sunny window ledge, or the dashboard of your car (parked in a sunny spot). Seed germination is notoriously uneven. One or two tiny seedlings may appear and then it may be several more days later before you see the next ones. As the first seeds germinate, remove the plastic cling wrap to avoid the seedlings damping-off and cover instead with a loose sheet of heavier plastic which does not seal around the container. Prick out into indivual containers when the seedlings have two or three leaves on them.