Avoiding Celery Heart Rot
17th Sep 1997
Trenching and Horse Manure
This year has been completely different with my first attempt at the local County Show giving me the first prize card. Part of the reason for this success has been the fact the piece of ground at the rear of my garden, just behind the polytunnels was well dug over last season with most of last years celery trenched into it. During November a trailer full of well rotted horse manure was spread over the whole area to a depth of at least four inches and thoroughly rotovated with the addition of 4 ounces of Chempak BTD to every square metre during April.
Another reason for the success has been the weather, although June was cold and wet, it really was good growing weather for celery with the sea breezes that we get in Anglesey being a contributory factor towards moving the air around the growing area. The seed that I had given to me from Bob Herbert at Mossborough was also a help, being a reselection of the prize winning Ideal strain with seemingly more length to the stalks as well as possessing a beautiful sparkling pink colour.
During early August I had a letter from John Mclauchlan Horticulture which extolled the virtues of a new product that they are now selling called liquid calcium. I have been aware for a number of years now that celery heart rot is occurring in the main because of the lack of calcium getting to the very young and vulnerable tips of the leaves in the heart of the plant. I have tried in the past to arrest the problem by using a 1% spray of calcium nitrate which in my case was not very successful.
Don't be misled into thinking that the lack of calcium in the young foliage within the celery heart is anything to do with a lack of calcium in the ground, it"s completely different. The problem is that the plant is unable to take up the calcium through the stems and into the tip of the growing shoots. The new product from John Mclauchlan Horticulture is an 8% liquid calcium compound which is used as a foliar application for the take up of calcium into the leaf. It is a fully organic chelated liquid calcium compound derived from Calcium Nitrate and trihydroxyglutarate organic acid that provides uniform availability of soluble calcium throughout the growing media.
I have used this on my plants towards the latter stages of growth and I have to say that at the time of writing, there doesn't appear to be any signs of heart rot at all. However further trials will be carried out next year to really ascertain if this is going to do the trick.
In addition to the above, all the celery this year was collared using the thin but stiff polystyrene backed foil that is sold at most DIY stores for use behind radiators to throw out heat into the room. This may well have been a contributory factor because it could have repelled the heat thus keeping the celery heart cooler. During late July and August the plants were draped over with some Papronet sheeting which, although clear, diffuses the penetration of the searing heat from the sun thereby preventing the plant from excessive transpiration.
I do feel that if the plant is transpiring at a fast rate, which inevitably happens on very dry sunny days, whilst at the same time unable to take up the correct levels of calcium to the young tips, heart rot will certainly follow. Of course spraying overhead with water will certainly reduce the incidence of transpiration but at the same time will keep the heart wet, this in turn will cause the young foliage to sweat and still rot away.
During all this the roots have to be kept constantly moist, never forget that the celery plant originally came form boggy areas where it thrived, so to assist in maintaining a high level of moisture in the soil the whole growing area was covered over with 3" (7.5cm) of well rotted horse manure which had been stored and covered over at the far end of the bed since last Winter. In between the two rows the centre path was covered with planks so there was hardly any area where the moisture could escape from.
More information on the liquid Calcium can be had from John Mclauchlan Horticulture, 50A Market Place, Thirsk, North Yorkshire. YO7 1LH or telephone them on 01845 525 585.