There is no attempt to provide a “how to grow a crop” guide.  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 a crop 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. 

Cress

Several plot holders are very enthusiastic about American Land cress. This is an alternative to water cress with the advantage that it does not require mountains of water to produce a worthwhile crop. It is a “cut and come again” variety.

Cucumber

Many people find greenhouse cucumbers to be slightly indigestible and prefer outdoor varieties that have a “meatier” texture. The only problem with outdoor cucumbers is that they tend to have tough skins and may need to be peeled.

The crop is relatively troublefree except for occasional problems with blackfly early in the season. Some plot holders let the plants trail over the ground, while others train them up poles to limit the amount of ground that they take up.

Crops are prolific in most seasons from early July until late September, and many plot holders end up giving lots of them away as there is only so much cucumber that it is possible to eat. Two plants are arguably enough to meet the needs of family and friends.

F1 Burpless Tasty Green is far and away the most popular variety, while Marketmore is also grown.

One plot holder grows gherkins (mainly Venlo Pickling) in preference to cucumbers.

Lettuce

There are 4 main types:

• Picking (or cut and come again). Lollo Rossa (extremely popular); Salad Bowl; Rocket (though strictly not a lettuce)
• Cos (seemingly less popular at the moment). Little Gem, Rusty (red) and Valmaine (resistant to warm conditions and slow to bolt)
• Iceberg. Ice King, while Webb’s Wonderful is an old and reliable variety
• Butterhead is arguably the most popular type currently. Fortune was an extremely popular variety but it is no longer available – everyone keeps hoping that it will return; Sangria – very slow to bolt but often slow to get going from the plantlet stage; All the Year Round; Unrivalled; Tom Thumb – good for an early crop, particularly when started under glass; and Cassandra.

There many colourful varieties now, some of which have been mentioned above. This useful RHS document (pdf) from 2003 describes many of them.

An early crop (early May) can be obtained by sowing indoors around the end of January, and planting out under a glass or plastic cloche in early March.

The major problem with lettuce is the tendency for an entire row to bolt at the same time in hot weather. Some plot holders combat this by sowing seed little and often, say a 4 foot row every 2 weeks from May onwards (in March and April it can be limited to once every 4 weeks). A second problem is downy mildew, which is increasingly likely as autumn approaches. Good hygiene and reasonable spacing between plants to encourage air circulation will help.

Other Salad Leaves

Alternatives to lettuce are quite popular among some plot holders. They include:

• Corn Salad (Lamb’s Lettuce) – its main attraction is that it provides leaves from November to January
• Radicchio - popular with some, while others find it bitter. Liable to bolt if sown before May. Not hardy.
• Rocket – generally popular, quick to grow, an alternative to cut and come again lettuces

Radish

The best summer radish, i.e. the crispest and least likely to be affected by pests, are those that are grown early in the season. The onset of summer (July onwards) generally sees a reduction in quality, irrespective of variety and watering, with root maggots frequently a problem. Flea beetle, which usually affects brassicas, can occasionally be a problem. Varieties seem to come and go with the odd exception. Current varieties in use include: French Breakfast (an old favourite), Pink Beauty, Jolly, Scarlet Globe, Cherry Belle and Sparkler 3.

Spring Onion

The majority of plot holders grow White Lisbon. However, it seldom grows successfully from later sowings. One plot holder recommends Laser for later sowings.