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Medwyn Williams

Hello. I'm Medwyn Williams – eleven times Gold medal winner at the Chelsea Flower Show, Past Chairman of the Royal Horticultural Society Fruit Vegetable and Herb Committee and President of the National Vegetable Society.

Traditional Trench Celery versus Self Blanching Celery


The difference basically between the two is that the trench variety needs to be earthed up in stages to blanch the stems where as the self blanching type needs to be planted in blocks or squares to blanch itself. The trench type certainly requires more commitment to thorough ground preparation but has, in my opinion, a far superior flavour.

Types of Celery

Sadly, only a few us seem to grow the old traditional trench celery these days, even though in my opinion, the flavour is far superior to the self blanching varieties. The trench type certainly requires more commitment to thorough ground preparation and must be partly the reason why gardeners have opted for the easier alternative. Most gardening books will tell you that trenches need to be opened up with copious quantities of manure laid on the bottom, it’s no wonder really that the old fashioned variety has fallen out of favour. I have to say though that on the show benches, the trench variety is still the one to beat.


The difference basically between the two is that the trench variety needs to be earthed up in stages to blanch the stems where as the self blanching type needs to be planted in blocks or squares to blanch itself. However even that terminology is really false, because what we are doing when earthing up or even collaring the celery is more than simply blanching. Blocking out the daylight will certainly blanch or whiten the stalks or petioles, but it also lengthens the stalks as it extends upwards in search of light. It is this fact in my opinion that makes the trench celery that little bit better because it reduces the stringiness of the stalk whilst the same time improving it”s flavour.


A friend once told me that celery seed were as small as Ants teeth, and that is small to say the least!. The fact is though that the seed of celery is the smallest of all the cultivated vegetables and it does need a little bit of extra care at sowing time. It’s certainly not the type of seed that you would sow directly outdoors, it has to be started off in a warm greenhouse and the initial use of an electric propagator would certainly help to speed up the germination rate. Fill a small shallow seed tray with some fine seed compost, level it off at the edge of the tray and then tap it down once on the seed bench. This will be sufficient to lightly compact the compost to make sure that there are no air pockets in it as well as leaving sufficient space at the top for watering. Pour out the seed from the packet into the palm of your hand and using your finger and thumb pick up the seed and lightly broadcast sow it on top of the compost. Lightly press down the seed into the compost with a flat piece of wood and place the tray in a suitable container with tepid water in it. Allow the compost to take the water in from the holes below, when the compost turns to a dark brown or black colour, the seed tray will be fully charged with water. The reason for watering this way, rather than with a watering can, is to prevent the sudden downpour of water from the cans” rose on top of the seed. This can have the effect of swimming the seed along the top of the compost ending up in clusters giving you a poor germination and leggy seedlings. Cover the seedlings very lightly, (they don’t need total darkness to germinate) with some fine grade Vermiculite and water on a daily basis making sure that the vermiculite and compost never dry out.

Growing On

Prick out into small pots when large enough to handle by the seedling leaf. Make sure, throughout their life in the pots, that the compost remains moist throughout. Plant them out into their final growing position making sure you have incorporated plenty of organic matter into the soil; again keep the beds moist throughout the Summer months. Celery is certainly not the easiest of plants to grow to perfection, but if you remember that it’s a hungry and thirsty crop, it will reward you well.


In it’s natural environment, the wild celery is effectively a bog plant, it loves having it’s roots continually moist and if you can emulate this sort of condition, then your half way to harvesting some cracking specimens.


One problem that can befall celery is the tips of the young leaves or shoots in the heart turning brown and eventually destroying the whole heart. The result means that no more stalks will develop and consequently the celery will be useless to eat.

This cultural problem (it’s not a disease) occurs because the young leaves are lacking in calcium at their tips and so start to rot off. It has nothing to do with the PH level in your soil and the imbalance can be corrected by watering with a solution of Calcium Nitrate into the heart and around the surrounding soil. Apply it at 5ml to a gallon of water and you’ll see the difference. I find this is prone to happen when the weather is constantly hot and humid, just before a storm. Apply this solution regularly, on a weekly basis, and you should keep clear of the problem.


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