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GROWING OUTDOOR CUCUMBERS
Forty years ago almost all cucumbers grown north of Watford by amateur gardeners were of the greenhouse type. In recent years cucumber seeds have been developed which are more than happy to produce excellent crops when grown outside in much of the UK.
Often this type of cucumber was referred to as a ridge cucumber because they were grown in mounds of soil designed to capture warmth, sunshine and provide good drainage. This is still an excellent method of growing them and it takes very little effort. They can however now be grown successfully on flat vegetable beds or raised beds.
DIFFERENCE BETWEEN GREENHOUSE AND OUTDOOR RIDGE CUCUMBERS
When you buy your cucumber seeds they will be classified as one of two types based on how early they can be sown in the year combined with how long they take to be ready for harvest.
- GREENHOUSE CUCUMBERS
These are classically grown varieties such as Bella and Pyralis. These varieties are only suitable for growing in warm temperatures such as those provided by a greenhouse. They tend to be longer than outdoor cucumbers. All greenhouse cucumbers will require frequent manual watering often as much as once a day. If you enjoy a summer holiday and don't have a trusted friend to look after your cucumbers daily while you are away then forget about growing this type of cucumber.
- OUTDOOR CUCUMBERS
Over the last 40 years or so excellent varieties of cucumbers have been developed for growing outside directly in the soil. These are sometimes called ridge cucumbers. Well known varieties include Marketmore. Many outdoor ridge cucumbers have small bumps on them although not all as La Diva proves.
The debate as to which type of cucumber tastes best, outdoor or greenhouse grown, will go on for ever but in blind tastings both came out about the same - see this Daily Telegraph article for informal tasting results of both types. Come back here though after reading it, for the ultimate guide on growing the tastiest outdoor cucumbers.
To adjust the dates in this article so that they are correct for your area of the UK
click here. There are significant climate differences
throughout the UK and setting your town will get the dates correct for you in your area of the UK.
If the dates are not set they will default to the UK average.
CALENDAR FOR GROWING OUTDOOR CUCUMBERS IN THE AVERAGE UK AREA
- Sow seeds indoors
- Sow seed under cloches outside
- Sow seed outside in open ground
- Harden off indoor grown seedlings
- Transplant plants to open ground
- Prune main stem
- Harvest ridge cucumbers from
The third week of April 2016
The first week of May 2016
Not warm enough in this area of the UK
The third week of May 2016
The first week of June 2016
The third week of June 2016
The third week of July 2016
BEST SOIL AND POSITION FOR GROWING OUTDOOR RIDGE CUCUMBERS
A position in full sun is the best one for ridge cucumbers, they will grow in partial shade but not as well.
As far as soil is concerned they do best in a neutral soil (neither acidic not alkaline) but they grow well in most soils as long as it's prepared well. The soil should be rich in nutrients, well drained but at the same time retain water - that's said for for a lot of vegetables but for ridge cucumbers it's more important compared to normal. They need water to bulk out the cucumbers but the plants and fruit suffer from mildew sometimes so the soil should also drain well to keep excess water away.
As far as crop rotation is concerned, ridge cucumbers can be grown anywhere in the garden or allotment. It's best not to grow them in the same position every year but they really don't encourage soil pests or diseases.
We describe below the classic way to prepare the soil for ridge cucumbers which may not always be possible but try to achieve as much as possible with the aim of having a rich, free-draining and water retentive soil.
Where the ridge cucumbers are to be planted dig out a trench which is 30cm / 1ft wide and about 45cm / 18in deep. Fill the trench half full with well rotted organic matter (from the compost heap is ideal) and then pile the earth on top. The weight of the earth will compact the organic matter but you will still be left with a ridge over the trench. This is now the ideal soil for growing ridge cucumbers. See the picture below for the basic idea in a picture.
Except in very warm parts of the UK the best method for sowing ridge cucumber seed is in pots, indoors. The best time to do this is in the third week of April 2016. If you really want to sow seed directly outside see our calendar near the top of this page for dates.
Ridge cucumbers are very productive if grown well, three to four plants will provide more than enough for a family of five. When planning how many seed to sow also take into account that a fully grown plant can easily take up 60 square centimetres (2 square feet).
During the third week of April 2016 fill a 10cm / 4in pot with normal potting compost to within 2cm of the top. Place one or two ridge cucumber seeds on the compost and cover with 1cm more potting compost and pat it down gently. Water with a fine spray to settle the compost down. Mark up with the variety name and place in a warmish, dark place (around 20°C / 68°F).
The seedlings will sprout above the surface after about 8 days and at this stage place the pots in a light position with a minimum temperature of 15°C / 60°F. Avoid placing the seedlings in direct sunshine because this may well damage their delicate foliage.
The cucumber seedling shown above is exactly two weeks after sowing the seeds indoors. You will note that we have highlighted a seedling which has only just appeared after that time. So although they normally appear after a week or so, wait for three weeks if nothing grows initially.
Ridge cucumbers can only be transferred to their final growing position
when all danger of frost has passed. But first they need to be
hardened off and
acclimatised to conditions in the open. Begin to harden them off in
tthe third week of May 2016 and then plant them out in
the first week of June 2015.
Planting them in their final position involves digging a hole slightly bigger than the pot, turn the plant out of the pot, place in the hole and fill in with earth. Water well to settle the soil down.
CARING FOR YOUR OUTDOOR CUCUMBER PLANTS
Watering is essential for a good crop if conditions become dry, weeding will also reduce water loss and competition for soil nutrients. You can erect mini-supports for ridge cucumbers but it's not needed at all. Just let them grow where they want and they will do fine. A two-weekly feed with a balanced fertiliser such as Growmore will help them along nicely.
Some gardeners mistakenly believe that, because the cucumber is fruit (it really is!), it does better if fed on a tomato type fertiliser which is higher in potassium than a balanced fertiliser but this is not the case. Indeed, it is a misconception that fruit producing plants in general need large amounts of potassium. For example apples, plums, peaches, pears, cherries and several other fruit producing plants require more nitrogen than they do potassium but in the case of tomatoes they require a higher percentage of potassium.
Cucumbers need high levels of nutrients to produce of their very best and nitrogen is as important to them as other elements. Our experience has backed this up as well and we have researched what other informed and practiced organisations say about this matter. Aside from the more commercial websites, some of whom have never grown their own cucumbers, we refer you to the following three well respected sites on this subject to back up our feeding recommendations:
- The RHS website who recommend "rake in 100g per square metre (3½ oz
per 10¾ sq ft) of general purpose fertiliser"
and later on "feed every 10-14 days with a balanced liquid fertiliser"
- The University of Illinois who recommend the following "side-dress
with nitrogen fertilizer when the plants begin to vine"
- Cornell University who recommend "Cucumbers are heavy feeders and require fertile soil, nitrogen fertilizer, and/or additions of high-N organic matter sources."
A mulch on the surrounding soil (but not touching the main stem) will conserve water and discourage weeds.
A small amount of pruning will encourage the early formation of outdoor cucumbers. The main stem will grow quickly once the plant is established - when it has grown eight sets of leaves pinch out the end of the stem. This will force the plant to put growth into the side stems and this is where your cucumbers will form. The date given in the calendar at the top of this page for pruning is very approximate so keep a watch out for the formation of those leaves.
In general, the rule with outdoor ridge cucumbers is not to remove any of the flowers - both male and female flowers are needed for pollination with the help of bees. However recent advances in the varieties available include a couple of so called ridge cucumbers where the difference between them and greenhouse varieties has becoming blurred. Our advice is to read the seed packet instructions carefully just in case some flower removal is recommended.
The calendar at the top of this page gives an approximate date when you can expect harvest your ridge cucumbers but in reality, the best indicator of when to harvest if the size of the growing cucumbers. When they reach a length of 20 cm or so they are probably ready to harvest. Different varieties may differ slightly so read the instructions on the seed packet.
RECOMMENDED VARIETIES OF OUTDOOR RIDGE CUCUMBERS
This variety looks more like a greenhouse cucumber than a ridge cucumber because the skin is smooth and they grow to about 30cm in length. Produces large numbers of tasty cucumbers.
The classic ridge cucumber awarded the RHS AGM a couple of times, this variety produces masses of dark green ribbed cucumbers about 20cm long. Tried and tested over many years, a very healthy variety.
Slightly shorter than average but the crop is plentiful and very tasty. Reasonably smooth skin makes slicing a pleasure.
PESTS AND DISEASES OF RIDGE CUCUMBERS
In our experience only two pests are a problem for ridge cucumbers. First and most likely are aphids, and the second is slugs and snails.
END OF ARTICLE