AGM 2015 – Gardeners’ Question Time

Questions for Chris Bird, Lecturer in Horticulture at Sparsholt College.

Q1. Cherries: A small cherry tree (variety Stella) planted 3 years ago. First year – no fruit (understandable). Second year – one beautiful cherry, third year (2015) produced a mass of cherries which never developed and then just dropped off the tree. Is it caused by something I’m doing (light pruning in the Summer and giving it potash once a year), not doing, or can I blame the cold weather this year?
A1. “Stella” variety is self pollinating. This year has been difficult with hot days and cold nights which cherries do not like, causing the fruit to drop. This is similar to Apples with the June drop. Dry weather made things worse. It is less likely to happen next year. Prune carefully and take off one third from top to get more fruit. Potash and wood ash is good.

Q2. Weeds: I grow prize-winning weeds: can I compost them (not including perennial weeds like bindweed, nettles, mare’s tail etc)?
A2. Nettles can be composted when not in flower. Use young nettles as a liquid feed. Hairy Bittercress is compostable and has a life cycle of about 12 weeks. Seed pods are dangerous as they explode and can get into eyes. When composting cover over with vegetable waste. Do not put Mare’s Tail or Bind Weed in compost.

Q3. Pond: My new little pond is doing well but I have to continually remove blanket weed. Will this gradually improve over time or will I be twiddling it out with a stick for the rest of my life?!
A3. This is a common problem with new ponds which should balance after a while. A third needs to be covered with plants. Barley straw can be used. It can be bought in a small biscuit form or in packs which can then be stuffed into tights. A dye can be used to stop it growing. Take any leaves out and net the pond.

Q4. Fruit trees: My fruit trees & bushes often get leaf curl. What’s the cause of this and how can I prevent it reoccurring please?
A4. This year has been a bad year for black fly. You can use Garlic juice. Small birds can control it. Grow Evening Primrose and Cosmos to encourage ladybirds. Soapy liquids can be used but do not over use. Better to use small birds to eat the aphids. If the leaves are affected it will still crop this year with good fruit. Use soft soap early in spring before flowering. A Peach tree variety named ‘Avalon Pride’ is leaf curl disease resistant.

Q5. Raspberries: Please can Chris talk about raspberry growing for beginners. How to prune and how to recognise the difference between summer and autumn varieties, especially when you have lost the labels!
A5. Buy stock from a good nursery. Raspberries are a woodland plant. Semi shade is good for planting in. Give nutrients and good mulch, own compost is good. They are greedy feeders. Do not dig around the roots. Buy the plants in Autumn. Plant 1ft apart in a single row or can be grown in a v shape to 1-2 meters high and run a wire through where they will get more sun on the fruit. If unsure if the plants are summer or autumn varieties then do not prune. Summer varieties fruit in summer and have canes which change colour. New canes will be purple without side shoots. Prune out old canes and thin ones. Then tie them in 4”-6” apart if using the Scandinavian system. Autumn varieties cut to the ground. They can be cut half way down to get a crop in June. Then cut right down. These are self supporting. Modern varieties have larger fruit and grow to 4 -5ft. Mulch heavily. Replace every 15 years. Plants can suffer from magnesium deficiency. Epson salts or Sea Weed can be used. They are most happy in acid soil of PH 5.5. Can be deficient in trace elements of calcium. New varieties for late summer are “Joan J” for flavour. “Autumn Bliss” is a good autumn variety also “Malling Leo” is good. Do not use Pro Grow on Raspberries. Can be watered but will need to be flooded then do not water for two weeks.

Q6. Tomatoes: First time problem of ripe sound greenhouse tomatoes splitting after they have been picked. How can I control/stop blight on my tomatoes?

A6. Some types are blight resistant. Use the same hygiene rules as for Potatoes. Infection can be spread from self setting Potatoes. Tools and boots can spread disease. Sanitise all tools and wheelbarrow wheels. Splitting is related to calcium deficiency due to the weather or if you use too much potash. Do not over feed. Grey mould is caused by lack of air movement. “Firline” is a blight resistant variety also “Green Zebra” is a good variety. “Sweet Aperitif” is a good cherry tomato. Beefsteak varieties are coming back. Greenback is when the tomato stays green in the centre. Be careful when tying in stems not to damage them. Have good air flow in the greenhouse.

Q7. Heirloom Veg: Do you have a web site address for Heirloom/Heritage vegetables and/or any recommendations of your favourite heirloom vegetables?
A7. These are becoming more popular. “Garden Organic” organises a heritage seed library scheme. Some National Trusts also have a heritage seed library. Some varieties are very attractive such as the Runner Bean named “Painted Lady”. Carrots can come in many colours but some can be hard in the centre. “Nicola Seeds” in Devon stock them.

Q8. Moles: My allotment, bounded by the road track on 2 sides over the last 4years has become a haven for lots of moles. To deter them I have used expensive pellets, traps, expensive solar operated bleepers & even tried hurling a garden fork when I spied motion under the soil— all to no avail. None of my neighbours seem to have any?? Any suggestions on getting rid of them will be welcomed.
A8. Moles do not like disturbance. Use plastic windmills for vibration. Sap from Euphorbia’s milky roots can irritate moles. Use a gorse bush in the mound or moth balls. A barrier may need to be put up. “Pyracantha” can also be used. If using a mole catcher they will not go near it if your scent is on it.

Q9. Runner Beans: Which is the best way to grow runner beans? Is it worth digging a trench to fill with moisture retaining material and maybe rotted manure or just to feed the surface soil before planting?
A9. Lots of people are going back to using trenches. An experiment between using rows or “teepee’s” style, showed results that “teepee’s” yielded a heavier crop. You need to dig a circular trench. Grow seed in root trainers under cover and harden off before planting. Do not disturb the roots and do not plant out too early. Make sure the supports are stable enough to support the weight. Can be cut down and grown as a perennial if mild, mulch them and see if they survive. They cannot be over watered. If they are dry you may get a dry set. Plants can be soaked once a fortnight.

Q10. Radishes: Every year that I grow radishes they are plagued by flea beetles. Is there a remedy for this pest?
A10. Use “Enviromesh” to cover plants. Possible causes could be due to the weather also Oil Seed Rape can encourage more flea beetles.

Q11. Sea-weed: Is it legal to take seaweed from local beaches? Do I need to prepare it in any way before putting it on my allotment?
A11. This can be taken from the beach in season usually between January and Easter. You will need to check with local Council for times. Harvest in sacks and tie the top because of flies and midges. It helps to get an old plot back into balance. It can be used in a compost heap. It is likely to have plastic bits mixed in with it but is good for trace elements. Do not rinse and use as a mulch. Salt in it kills slugs. It can be used on cabbages.