Roehampton Garden Society

Tag Archives: Potatoes


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The problem with Charlotte..

A conversation in the Store one Sunday led to Jackie Savage contacting the RHS helpline about a problem with Charlotte Salad Potatoes this year…

Jackie says:

I have a plentiful harvest from the seed potatoes I planted in March but when I cook them I find that they are not the waxy, pale yellow salad potatoes that I love. I clean them and leave the skins on and then boil them for 8 to 10 minutes. The skins fall off but the potato is white and floury. I cannot use them to make potato salad as they do not hold their shape, but they are tasty as mash. I was not the only one to experience this so I wrote to the RHS helpline and received this answer:

This breaking down of the potato is known as sloughing. The exact cause is unclear. Potassium deficiency has been discussed and, as sulphate of potash is fairly cheap and widely available, adding this at 20 g per sq yard would seem be worth trying. It is reported that disintegration decreases with storage and it may be that the potatoes will be better after a few months of storage.
It is said that adding some bicarbonate of soda to the cooking water helps maintain the intercellular bonds and reduces sloughing. It would be interesting to know if microwaving, baking and steaming also led to disintegration.

RHS Helpline

Jackie would be really interested to hear if anyone else has had the same experience and if they have any suggestions or solutions. She says: “Perhaps I should give up on Charlottes and grow a different salad potato? Or add sulphate of potash at the time of planting? I am reluctant to add bicarbonate of soda to the cooking water.”

Have you had a similar experience this year – or have you any advice to offer? Please email your suggestions to rgs.sw15 @gmail.com


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January jobs on your allotment

Maintaining soil and structures and planning ahead

  • As crops are harvested clear debris and cover cleared soil with weed suppressant.
  • Plan a crop system for vegetables- leaving a minimum of two years before replanting crops in the same place.
  • Complete winter digging of bare beds and cover the ground to warm beds for early crops.
  • Open greenhouse vents on mild days
  • Clean greenhouses, staging, pots and seed-trays for the coming growing season.

Sowing and growing

  • Apply winter washes to fruit trees to control overwintering pests.
  • Start ‘chitting’ tubers of early potatoes in trays in a cool, light, frost-free location.
  • Sow broad beans in pots under cover.
  • Sow winter salads in a greenhouse or windowsill.
  • Sow summer brassicas and spinach on a windowsill to plant out in late February.
  • Aubergines can be sown under cover on a sunny windowsill from late January.
  • Bring potted runners of strawberries under glass for forcing.
  • Sow later sweet peas now and pot on autumn-sown sweet peas, pinching out the tip after 4 pairs of leaves have developed or when plants have reached 3.5 cms. Place on a sunny windowsill, in a cold frame or greenhouse.
  • Ensure brassicas are protected against pigeons by netting.
  • Begin forcing rhubarb for an early crop by placing a bucket or forcing jar over the crop.

Harvesting

  • Harvest parsnip, swede, sprouting broccoli, Brussels sprouts, leek and turnip.

Pruning

  • Prune overgrown blackcurrant bushes- remove a third of the old, weak or unproductive stems to ground level to encourage new basal shoots.
  • Prune freestanding apples and pears, maintaining an open centre. Do not remove more than 20% of the crown in one winter
  • Prune gooseberries, redcurrants and whitecurrants by removing dead wood and low lying shoots. Prune last year’s growth of the main stems by about a half. Prune all side-shoots back to one to three buds from their bases.
  • Prune grapevines before mid January.

Gardening for wildlife

  • Regularly replenish bird feeders.
  • Clear out bird boxes by removing old nests and rinse out boxes.


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August jobs on your allotment

Maintaining soil structures and planning ahead

  • Green manures such as Mustard and Phacelia and Grazing Rye can be sown now.
  • Continue regular weeding to avoid build-up of work later.

Sowing and Growing

  • Sow oriental vegetables such as mizuna, pak choi and mustard greens for salad leaves- they bolt less at this time of year.
  • Sow parsley to last through till spring on a sunny windowsill.
  • Sow Swiss chard and perpetual spinach at the beginning of the month.
  • Make a last sowing of beetroot at the beginning of the month.
  • Sow fast-growing ‘catch crops’ for autumn use, such as radish, lettuce, rocket and turnips.
  • Plant out winter brassicas, broccoli, kale and cabbbages in soil which has been limed at least 6 weeks before, to reduce club root infestations.
  • Plant new strawberries now, either as detached runners or new plants.
  • In dry weather keep runner beans well-watered twice a week to aid setting.
  • To reduce risk of tomato blight, water directly onto the roots not the leaves.
  • Feed courgette plants weekly with a high potash liquid feed to continue fruiting.
  • Summer prune trained fruit trees such as fans, espaliers and cordons.
  • Prune plum and damson trees after fruiting. On grape vines shorten fruit bearing branches to two leaves beyond the fruit bunch.
  • Prune out fruited canes of summer raspberries.
  • Tie in new canes on raspberries and blackberries.
  • On grape vines shorten fruit bearing branches to two leaves beyond the fruit bunch.
  • Cut back chives if showing signs of rust and new shoots will quickly appear. Remove mint plants showing signs of rust. The disease will persist over winter and re-infect new plants next year.
  • Pick off and destroy rosemary leaf beetle which are active at this time of year.
  • In the greenhouse avoid splashing water onto leaves. Moisture triggers spore germination of fungal diseases.

Harvesting

  • Harvest sweet corn when a grain exudes milky juice when tested with a fingernail and the whiskers are brown.
  • Harvest onions and shallots when the stems are dry and papery.
  • Start harvesting runner beans, parsnips and cucumbers when ready.
  • Complete harvesting of second early potatoes and begin to harvest main crop potatoes as they begin to flower.
  • Harvest early ripening apples and pears.
  • Harvest carrots, but leave protective insect mesh on carrots until autumn.

Gardening for wildlife

  • Leave some flower seed heads on plants as source of food for wildlife.
  • Cut and shake ripe seed heads of annuals over suitable patches of bare soil for flowers next year.


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June jobs on your allotment

June Foxgloves

Maintaining soil structures and planning ahead

  • Continue to hand-weed or hoe regularly to keep on top of weeds.
  • Dig deep to remove highly invasive bind weed as it appears.
  • Continue to mow or clip grass paths weekly.
  • If you have sown green manure, dig it in this month to fix the nitrogen in the soil.
  • In the greenhouse ensure adequate shading. Check night time temperatures and close door on cold nights. On hot days keep greenhouse temperatures down by using maximum ventilation and damp down greenhouse floors to increase humidity.
  • Use insect-proof mesh over carrots to prevent carrot fly attacking carrots. Ensure it is well-pegged down, not leaving any gaps.
  • Use insect-proof mesh over leeks to prevent leek moth damaging leeks. Ensure it is well-pegged down, not leaving any gaps.

Sowing and Growing

  • Direct-sow courgettes.
  • Sow radicchio in drills for autumn salad leaves.
  • Sow fennel and oriental greens such as mizuna and pak choi. June sowings reduce the risk of bolting.
  • Successionally sow salads, rocket and basil etc every two to three weeks for continuous picking.
  • Make a late sowing of peas for an autumn crop.
  • Sow overwintering carrots such as Autumn King or Chantenay.
  • Quick-maturing radishes or salad leaf crops can be sown between brassica rows.
  • Quick-germinating annuals, such as cosmos, that attract insect pollinators can still be sown.
    Sow wallflowers for next year.
  • Water potatoes well for good-sized tubers and reduced problems with scab. (Remember to target-water, not spray, to avoid water wastage.)
  • Water tomatoes regularly and evenly. Uneven watering can cause cracked fruit and blossom end rot. Regularly pinch outside shoots on cordon tomatoes and tie in plants to supports.
    Feed every 10-14 days with a liquid fertilizer, changing to a high potash fertilizer once the first fruits begin to set.
  • Plant out sweet corn 16” apart in blocks, not rows, to aid wind pollination.
  • Continue planting out or direct-sow runner and French beans.
  • Transplant pencil-thick leeks now into 6” deep holes.
  • Plant out pumpkins, squashes in well manured ground. Plant out outdoor cucumbers and peppers. Protect with fleece on cold nights.
  • Keep fruit bushes well-watered. (Target-water, not spray, to avoid water wastage.) Protect soft fruit from bird attack by netting securely and tie in new raspberry and blackberry canes.
  • Continue to check for sawfly larvae on gooseberries. Hand pick off.
  • Remove strawberry runners during the early part of summer, to avoid energy being diverted from the developing fruit.
  • On plum trees, after the ‘June drop’ of excess developing fruits, thin the fruits to prevent overladen branches breaking.

Harvesting

  • Continue to regularly harvest established asparagus – mid April to mid June. If asparagus growth is weak, apply a general fertilizer of fish, blood and bone.
  • First, second and salad potatoes may be ready for harvesting. Tubers should be ready when plants begin to flower.
  • Harvest broad beans from the bottom of the plant up. Once the plant is harvested, cut off the stems and dig the roots back into the soil to make use of the captured nitrogen.
  • Harvest early peas. Put unused pea pods and foliage into the compost heap or dig into the soil to provide nitrogen rich nutrients to the soil.

Gardening for Wildlife

  • If broad beans are affected by blackfly, rub off or spray with a jet of water to remove them rather than using insecticides.
  • Create a cool, damp spot for amphibians and their prey to take shelter in by building a log pile in a shady corner. Half bury the bottom logs and fill nooks and crannies with leaves.
  • Add a bee house to your plot or garden, placing it in a south-facing spot but not in direct sunlight.
  • Select single forms of annual flowers as these provide more pollen for bees. Integrate annual flowers into the vegetable beds to attract beneficial insects such as bees and hoverflies.
  • Reduce the use of herbicides, fungicides and insecticides if possible.