'Willpower & sheer idiocy combine in harmony'
No dead sheep necessary for bunches of grapes
AN old colleague advised me to bury a dead sheep outside my conservatory and plant a grape vine on top of it, training it inside.
I declined his advice, and waited another 25 years before deciding to give grapes a go.
While it's true that planting vines outside and fruiting inside is an accepted practice, there's no way I'm going to remove any glass from the greenhouse.
You're only going to need one vine - they need a lot of room. However, if you live at Chatsworth, allow 1m between each vine.
My little Muscat grape is tiny, bought on a whim from Harperley Hall Farm Nurseries. I repotted it, with the aim of planting into my greenhouse border in November (it can be pruned back without bleeding at this time of year).
It's a modern white dessert/wine grape with yellow-green berries, sweet with a light muscat flavour. it has mildew resistance and is heavy cropping.
Feeding frenzy
Grapes are very greedy. When my vine goes into the greenhouse border, the soil needs to be enriched with well–rotted manure or compost, plus John Innes base fertiliser at 90g per sq m (3oz per sq yd).
Just before growth starts in spring, add more John Innes base fertiliser and dried blood, fish and bone (or equivalent) at a rate of 120g per sq m (4oz per sq yd), then mulch with well-rotted manure.
During the growing season, add more dried blood at 30g per sq m (1oz per sq yd).
When growth starts, feed every three weeks with a tomato fertiliser. Once in full leaf, increase this feeding to weekly. When the grapes start to ripen and colour up, stop feeding with tomato feed.
Water the vine thoroughly every seven to 10 days in the growing season. Vines with the roots inside the greenhouse will need more frequent watering.
During summer, mulch the borders with straw to keep the atmosphere dry. This will aid pollination and fruit set.
Every few years, dig a trench about 2m from the main stem, deep enough to reach any rubble put in to improve drainage.
Backfill with fresh topsoil. That will be a feat, as it's bigger than my greenhouse.
To help pollinate greenhouse grapes, at noon on a sunny day, shake the stems briskly but firmly, or stroke a cupped hand over each bunch of flowers, to transfer pollen between the flowers (most reliable for Muscat-type grapes).
Growing grape vines under glass
Vine pruning & problems
Pruning and training
AS a general rule;
Vines growing against the side of the greenhouse are trained and pruned according to the rod and spur system.
Vines in pots or where space is limited can be pruned and trained as standards (I'll do more on this when I have something to prune).
Problems
Grape vines suffer from a lot of diseases - their reputation as difficult is not unwarranted.
Of these, powdery mildew is perhaps the most common, striking in hot, dry weather or when growing in crowded positions with poor air circulation.
They can also suffer from grey mould (Botrytis), downy mildew, magnesium deficiency and the physiological disorder known as shanking.
Wasps can be problematic, and it is a good idea to hang wasp traps near the vine, especially with early-season grapes.
'Beulah, peel me a grape!'
Never mind Mae West's immortal line - thinning gets a good bunch
SIZE, sweetness and quality of dessert grapes are improved by thinning with special scissors with long, narrow blades.
This encourages even ripening and discourages fungal problems.
Vine scissors thin the grapes within each bunch. Steady the bunch with a small forked stick, as using your fingers spoils the bloom on the skins.
Thin twice, first when the grapes are tiny, and then again when the grapes have increased in size.
Tendrils are thin, twisty stem-like structures that curl round supports - remove these as they form.
Grape vines like well-ventilated, warm, dry conditions.
Although heat is increased by keeping the vents closed, this will result in a build-up of humidity in the air that could result in fungal diseases and decrease pollination rates.
Keep the vents open during the summer and autumn, especially around flowering and fruiting time.
Small but perfectly formed - my little Muscat vine.
