
Q. We have just started a small soft fruit business. We have early, mid and late raspberries, black, red and white currants, gooseberries and blackberries. The soil is light loam with neutral pH and a deficiency of zinc. What fertiliser would you recommend to start and which for on-going feeding. A. You can tackle the zinc deficiency using HORTICHEL ZINC from Hortifeeds. This should be sprayed at 1 litre per hectare in 500 – 1000 litres of water. A regime of liquid feeding would be ideal for your general requirements. The first step would be to analyse your water and then match HORTIMIX FRUIT soluble powders to the results. The following analyses provide a guide: First feed to flowering 21 – 7 – 21+TE Flowering to Fruiting 12 – 3 – 36+TE or 15 – 7 – 30+TE (both are high potassium feeds). End of fruiting to End of Season 15 – 7 – 30+TE (this contains a slightly higher phosphorous level to ensure best start in the following season). Q: I have been growing Prims for a few years and this year I have noticed a problem of yellowing on the young, new leaves which has been getting progressively worse. Please could you tell me what is causing the problem and what can be done, if anything, to remedy it? A: The yellowing on the younger, newest leaves is most usually a common symptom of iron deficiency. This type of problem is quite common in areas of hard water with high levels of bicarbonate. The high bicarbonate results in a pH rise in the compost which causes the iron to ‘lock up’ and become unavailable to the plant. A short term, curative measure for the problem would be the addition of an iron product such as Hortichel Iron to the feed programme. This can be added to the stock solution at the rate of 150 ml per 100 L stock with the dilutor set at 1%. I would hesitate to recommend a foliar spray as Prims under glass would be quite sensitive to scorch from foliar sprays. The long term cure for this problem would be to attempt to lower the pH and displace some of the bicarbonate. This can be achieved in several ways. The easiest way would be to consider the use of Hortimix Extra soluble powder feeds. When used, these powders will displace some of the Bicarbonate in the water resulting in a lower pH, thus making the iron more available. Another option would be to consider the use of Nitric Acid in the stock solution. The amount of acid can be calculated from the known quantity of bicarbonate in the water. Obviously there are Health and Safety issues to consider with this option. Q: I am a Vegetable transplant raiser growing in very soft water. I have been recommended using a special soft water mix containing calcium. Do you think that this is right for me? A: Obviously giving detailed recommendations with a limited amount of information is very difficult. Normally before giving a feed programme, we would like to be provided with all relevant data such as water analysis results and some information about cropping and growing media. To give some general guidelines, I would suggest that you be very careful when using these mixes that contain calcium. In areas of very soft water, many growers have experienced problems using these products. The biggest danger is one of reducing the pH of the feed solution too far as these products actually contain strongly acidifying powders which can bring the level of the pH down to dangerous levels. A problem is that they also usually contain high levels of nitrogen in the form of ammonium which can depress dry matter accumulation in young plants and compete with calcium for pH uptake. My recommendation would therefore be to use the Hortimix range of High Nitrate Soluble feeds. These fertilisers contain the majority of the nitrogen in the form of nitrate. The high levels of nitrate will improve the dry matter content of the plant and also encourage calcium uptake which results in sturdier, healthier growth. For fast growth I would recommend the Hortimix High Nitrate 3-1-3 (20.5-6.8-20.5) at the rate of 0.5g/L. For slower, sturdier growth I recommend Hortimix High Nitrate 2-1-4 (15-7-30) at the rate of 0.5 g/L. Feed every watering for 2 – 3 weeks after sowing.