There is no attempt to provide a “how to grow a crop” guide although, in general, there tends to be more information on crops that are not widely grown.  This is simply an attempt to distil the experiences of different plot holders in the hope that you will find the occasional observation on varieties or approaches to cultivation that is new and (hopefully) useful. Clicking on the heading for the majority of crops will bring up a background article on it from elsewhere on the Web in a new window; the majority have been garnered from Wikipedia, the free online encyclopaedia that anybody can contribute towards. The quality of these articles varies: as with most topics on Wikipedia, some are very comprehensive, while others are not so thorough. Other links are periodically scattered through the text. Any recommendations on links to better background articles or additional links to items of note will be gratefully received. 

Oca

Nobody on the site has grown Oca so far. I have included it because it is generating a lot of interest among UK allotment holders.

It hails from the central and southern Andes and it is grown as an alternative to potato. The tubers are small, the crop smaller than potato, and it has a sweet edge. It requires a long growing season with the crop being harvested in late November or early December.

Here is an excellent article on growing Oca by David Frary, a keen allotment holder from Brent. Tubers can by obtained from RealSeeds.

Onion

Onions are started either in Autumn or Spring. Senshyu, a successful Japanese Bulb Onion for early harvesting, is sown in the Autumn. Onion sets for autumn planting include Radar and Unwin’s First Early (variable results). Most plot holders grow from sets in the Spring. Varieties include: Setton, Centurion, Sturon, Turbo, Snowball (a white onion that stored well) and Red Baron

A small number of plots have areas that suffer from onion white rot disease. This is a soil-borne disease that can stay in the ground for 20 years and effectively precludes the growth of the crop. Also, downy mildew has been a problem in recent years. It can reduce the crop and the keeping quality of the bulbs. Spraying with Dithane, which provides a physical barrier, is sometimes recommended but it has been used without success.

Parsnip was a staple part of the British diet before the potato was brought to this country. The stony nature of our soil can lead to forked roots. Some plot holders dig holes where the seed is going and painstakingly remove the stones. Parsnip is very slow to germinate and can be difficult to spot among the weeds. It can be helpful to sow a quick growing crop such as radish very thinly along the row (1 seed every 5-6 inches) to show precisely where the row is when the weeds come up, with the added bonus that it will provide a catch crop for salads before the parsnips really get going. Parsnip seed does not remain viable and should be bought fresh every year.

It is usually grown for winter consumption; it is said that they have more taste once they have been frosted. Canker can be a problem, getting worse as the winter progresses, particularly in wet seasons. Early parsnips can be harvested in August although they have to be started indoors in January. One plot holder uses the cardboard cores of toilet rolls filled with compost. Summer parsnips do not suffer from canker, but they lack the flavour of the winter crop.

No variety is immune to canker, although several are advertised as having resistance. Tender & True, Gladiator, Avon Resistor and Albion are the main varieties that are grown.

Some people find boiled or mashed parsnips slightly bitter; roasted parsnips are (somewhat amazingly) sweet in comparison.

Mice are attracted to the seed. An old remedy is to dip the seed in paraffin before sowing. On the same theme, the perimeter of the pea bed can be sprayed with paraffin to deter them. Pigeons have become attracted to peas and mangetout in recent years and some form of protection is required, e.g. netting. Covering the ground with fleece will help to protect the seedlings initially, and it seems to make life a bit more difficult for the mice. The other problem is the pea moth which results in maggots in the peas. Pheremone traps provide a biological control; alternatively, spray with derris just before the flowers open. One plot holder successfully uses Enviromesh fleece to keep the moth at bay.

Varieties that are grown include:

• Early pea. Early Onward, Kelvedon Wonder and Feltham First
• Second early pea. Hurst Green Shaft is very popular
• Maincrop. Good initial report from GreenSage (Greenshaft type – new in 2006)
• Mangetout. Oregon Sugar Pod is popular.

As everybody knows, peas freeze well. Mangetout can be frozen (after blanching) but they become somewhat watery and lose their “crunch”.

The crop requires a reasonable summer for successful outdoor growing. 2005 was classed as a reasonable year, while 2006 was a bumper year. This is a very useful chilli-specific web site.

Hardened-off plants are put out around the end of May. Once they are established (around the end of June) they do not appear to require much water.

In general, the smaller the fruit the hotter it is likely to be. Similarly, red fruits are likely to be hotter than green fruits although very few fruits will turn red outdoors in a British summer. Dried chillies are hotter than fresh ones. The variety Hot Stuff produced large fruits which were relatively mild, contrary to what the seed catalogues say; F1 Apache has been grown under glass and produced quite hot fruits.

They can be frozen whole after removing the tops (no blanching required), and they can subsequently be used in chilli-based stews such as chilli con carne.

This is a relatively troublefree crop with prolific crops in most years. They are planted out around the end of May when the danger of frost has disappeared. Several plot holders provide some additional protection by putting the plants in a cloche or cold frame around the end of May until they are bursting to get out, usually around the end of June, when the protection is removed.

 Varieties which are grown include: Gypsy (slender pale green fruits shown in the picture on the left), WorldBeater, Sweet Delight Mixed (bumper crop of green, yellow and red fruits in 2006) and Ruby King / Golden Queen (a mixed packet).

The peppers can be cut into large pieces and frozen (no blanching required) for subsequent use in cooked dishes.

Potato

There is no consensus with respect to varieties, and plot holders tend to change for reasons which include: scab, which is unsightly but does not affect the crop; individual preferences for waxy or floury potatoes; varieties that do not cope well with very dry conditions; and concerns over blight (more likely with maincrop potatoes). Early blight tends to result in a reduced crop; late blight is more damaging. Blight is further discussed under Tomatoes. Varieties of potato being cultivated include:

• First Earlies. Foremost, Accent, Orla (resistance to blight), Duke of York (but does not keep),
• Second Earlies. Nadine (new), Maris Peer, Estima (variable feedback), Bonnie and Romano
• Maincrop. Desiree, Maris Piper, Valor (good general disease resistance, including blight, but small crop in 2006), Romano, Cara (variable feedback) and Sarpo Mira (a red potato with good disease resistance, including blight, but poor taste)
• Salad Potato where the caveat is not to grow too many plants, as it is only possible to eat so much salad potato. Consider sharing a bag with other plot holder(s). Charlotte and Pink Fir Apple (old variety but low yielding) are recommended.

See the British Council's Potato Variety Database web site for information on individual varieties, including how susceptible each is to diseases such blight. The Council's main web site contains much useful information, including information on pests and diseases.

Spinach is prone to bolt on our soil, particularly in dry periods. For this reason almost all plot holders grow Perpetual Spinach, which is in fact a leaf beet. It has a slightly harsher taste than spinach but, apart from being slow to run to seed, it is hardy and can survive well into early winter and beyond. F1 Detona, a true spinach, was grown successfully in 2006.

Spinach is one of the earliest crops, the first picking usually occurring at the beginning of June from an early-mid April sowing. If the crop is not picked at the height of summer, usually because there are so many other crops to be harvested, the plants can be cut down to 2-3 inches from the ground in August when the plants are starting to get out of control and the leaves are becoming coarse, and they will grow again to provide young leaves from September onwards.

Spinach freezes reasonably well - shredded and blanched.

Swiss Chard is an alternative to Spinach. It can be eaten raw in salads or steamed. Bright Lights, which has the additional benefit of being quite decorative, has been grown successfully.

Butternut Squash is the most popular form. It requires a reasonably long growing season; it is preferable to sow indoors in early to mid-April and plant out at the end of May. Outdoor sowing in mid-May is possible, although somewhat problematic. The plants prefer soil that is rich in organic content; they can be grown on a compost heap, similar to pumpkins. Avalon is a reliable variety. Rugosa, an Italian variety that was available in Longacres, has also been grown successfully by several plot holders.

The plants produce an abundance of male flowers initially. It is recommended that the tips are pinched out after 6 leaves to encourage female flowers to form. Fruits, 2-4 per plant, will eventually tend to appear around the beginning of August. Check them regularly and remove any dying flowers from the end of the fruitlets, as they can become a receptacle for rain water and lead to rot.

Leave the fruits to ripen on the plant (they will go beige), leaving an inch or two of stalk on the fruit when you cut them. They are unlikely to ripen further on the plant after early-mid October although they can be ripened further if they are placed in a bright warm spot, e.g. greenhouse, conservatory, or sheltered south-facing wall. The fruits will store longest, possibly to the end of February according to the books, if the temperature does not go below 10C. The end of January has been achieved by keeping them in the garage except during cold spells when they have been brought inside. One person recommends storing them in old tights with a knot between each plant to avoid them touching. Check the fruits periodically; any rot is more likely to appear where the stalk meets the fruit although it can occasionally surface at the other end where the flower was originally.

Butternut squash has a sweet edge to it, which usually makes it appealing to children. It can be cooked in a variety of ways: roasted – peel skin off, cut into wedges 1½-2 inches (4-5cm) square and cook at 190C for approximately 60 minutes (less if the wedges are smaller) - they can be cooked alongside roast potatoes; baked - cut fruit in half lengthways at 190C for 45-60 minutes; soup – there are many recipes that can be found on the Internet; and even as a dessert pie (similar to pumpkin pie) although it will require additional sweeteners.

Swede seems to have been out of favour in recent years. One plot holder grows the variety Ruby with mixed results, several excellent-sized roots interspersed with many skinny, unswollen roots.

Sow indoors in mid-April and plant out in late May. As the books recommend, it is best to plant in blocks to aid pollination. Outdoor sowing can take place in mid-May. Bird protection is required until they are well established. Crisping up of the tassles at the top of the cob is the sign that it is ready to pick.

F1 Sundance is a popular variety that crops well, as it is bred for indifferent British summers. LArk has been grown with reasonable results while F1 Minipop which produces baby corn has been tried with variable results.

Common Smut is a disease that is widespread in the US , but only seems to occur spasmodically in the UK – one plot holder has reported signs of it in 2006. The swellings (or galls as they are called) will, if they are not removed in time, explode and spread their spores on the surrounding soil. The books recommend that sweet corn is not grown for 3-5 years on any infected area. The link contains some good photographs to help identify the disease.

Tomato (Outdoor)

Tomato is best grown in an area that has been enriched with well-rotted manure or compost. One approach is to take out a square “pocket” of soil (one spade wide, long and deep); put manure or compost in the hole; add a pinch of fertiliser (general or potash-based); put the soil back on top and allow the ground to settle, marking the spot where the pocket is; and finally place the plant in the middle of the pocket area around the end of May.

Any form of protection from the elements will help to encourage growth and produce earlier fruit. Examples include the use of a mini (home-made) poly tunnel which can also help against blight, and a perimeter of corrugated plastic (60-70cm high) around the tomato bed.

Tomatoes, being a member of the potato family, are susceptible to potato blight if grown outdoors. Blight, a fungus which prospers in warm, moist conditions, can arrive from early July onwards although in most seasons it does not appear until early to mid September. In some years there is little or no blight. As it is a problem to farmers and professional growers, there is a blightwatch service (although you have to register at potatocrop.com to use it). There is no variety that is totally resistant although some do have degrees of resistance. Use of a copper fungicide spray (such as Murphy’s) is generally recommended every 14 days as a preventative measure, although it is not necessary in dry periods. This provides a purely physical barrier to the fungus on the surface of the plant and fruit (obviously wash any fruit before eating). Check the foliage every couple of days and remove any diseased foliage as soon as it appears.

Feeding approaches vary: some plot holders use proprietary potash-based products; a couple of people make their own liquid feed with nettles or Comfrey (see Garden recipes); while another uses a pinch of sulphate of potash at planting time but does not feed thereafter.

Varieties fall into three main groups:

• Small sweet fruit. Many plot holders grow them; Gardener’s Delight is very popular
• Medium-sized fruit with good flavour which can be eaten or cooked. Tamina (relatively popular as it appears to have some resistance to blight); Alicante (often grown in greenhouses as well); Tornado - a bush variety with thin skins that does not need any training, e.g. no need to pinch out sideshoots, although any branch that is very heavily laden with fruit may need some support to prevent it snapping; Ailsa Craig and Harbinger
• Large fruit, sometimes called beefsteak, which are particularly suitable for freezing for use in soups and sauces. Marmande is an old reliable variety, while Fantasio (new in 2006) has some resistance to blight.

Tomatoes can be frozen in “sauce” form: whiz the fruit in a blender; boil in a large pan, reducing by a factor of 3 or 4 until most of the liquid has evaporated and a thickish paste is left; store in usable-sized portions in the freezer for use in soups and tomato-based sauces.

Several people make ratatouille with their own crops and freeze it. There are various recipes but the majority include tomato, onion, garlic, aubergine, sweet pepper, and courgette.

Turnips are not currently popular. They are best harvested small, tennis ball size or preferably smaller, as otherwise they will have a tendency to go woody. Rubin did well in 2006 while Snowball is a well-established variety.