Worked with Mario, who looks after the model vegetable garden, a demo area for the public. It is made up of a series of raised beds. Mario can grow pretty much what he wants there, the only remit is that the varieties are obtainable by the general public. He always try to get disease resistant varieties but will grow things that are commonly grown by everyday people. He works on a four year rotation and plans the planting anew every year on this basis. The whole area is on a bit of a slope slightly inclined to the north. It's not a straight rotation, where everything just moves along a bed, certain positions are only suitable for certain things, for e.g he can't grow something tall where you can see it from the rose garden, to not interfere with the design there.
I helped him pull out a bed of cauliflower called 'April' and cleared it. It had gone over and not done so well. They also had club root. The way he deals with this disease prevalent in the soil of some of these beds is through the rotation and by growing resistant varieties.
Things he will be popping in at this time of year are more runner beans and kohl rabi (grown covered because of brassica root fly).
He demonstrated how he grew his cucumbers, he always grow them in a glasshouse with a drip irrigation system. He doesn't like growing them outside because the skin gets tough and spiny, and the fruit can have a tendency to be bitter. He trains them on vertical lines, a string around a grow bag with the top and bottom at approx. 45 degrees angles (using canes as an aid). He grows modern varieties that are female, cucumbers are usually dioecious, but if there are males (where the flowers are on the end of stems rather than fruit), he pinches these out, as cross pollinated with females the cucumber will want to produce seeds and the fruit will be bitter. He likes them straight too and the key to this is to train the fruit not to be touching each other. He lets a a sideshoot grow from an internode, this is then cut down to two leaves, this is a way of thinning the plant and the fruits. At the top of the plant he allows two side shoots to grow, the leader is continually cut to not outgrow its line and the glasshouse to control the vigour. He particularly thins the plant at the lead axils too. Cucumbers are prone to mildew. They are fed when the leaves start going lighter. If young fruit and pedicel goes yellow that is the fruit aborting itself, these are taken off to avoid botrytis. Care is taken for the main stem not to be affected. Commercially grown they are trained 5m high, a system where lines can be slackened and lowered down for fruit to be picked.
Peas often suffers from magnesium deficiency, this is treated with Epsom salts. To help them along, potash of sulphate can be put on the ground before seed sowing. When peas are finished they go dried and yellow, this can be a sign of mildew also.
I helped weed aubergine under glass cloches, these can be left open at this time of year, if temp. doesn't go below 10 degrees. They are drip irrigated on the surface, but the disadvantage of this is that the roots only concentrate on the surface, so we had to carefully hand weed. They are most vulnerable to soil bourne diseases Sclerotina and Rhizoctonia. Leaves are not touched when watering if possible.
A lot of his plants he feeds with Tomorite, which containing potassium can hold back calcium - it gets locked in the soil, so then Epsom salts is used to treat this, which also helps release magnesium. A manganese foliage feed is used (Maxi-crop - essentially a seaweed extract), if there is this deficiency, only spray on a downcast day that stays like this for at least a few hours,so the leaves don't scorch. When weather is not good, nutrient deficiencies show more.
When treating ND you can't remedy the affected leaves, recovery will only show in new ones.
Tomatoes - Mario still grows heritage varieties, rather than just f1 disease resistant ones because of the taste. Tomato skin is very thin, so sensitive to watering. Heritage ones usually have big tobacco plant like leaves, whilst commercial ones are cut leaves. In order for a variety to be commercially viable, it has to produce 50 kilos per sqm. If leaves curl at the top inwards, this is usually a sign of virus. If outwards it is a sign of dryness, this is because the leaves wants to get close to the hairiness of the stem where there is a chance of moisture. He also doesn't bother with growing these outside because there are more problems to contend with.
Courgettes - if they go yellow at the ends and starts rotting or misshapen, like cucumber that is the fruit aborting. Technically it's a kind of blossom end rot It could be the cause of drought, erratic water, calcium deficiency or poor pollination especially on dry days. Pollination has to happen 50 times between each plant. Cucumbers and courgettes need a pint of water per plant. For the drip irrigation Mario measured that it is leaving it on for 20 mins for adequate amount.