Whilst
Leeks occupy the ground for a good portion of the year, they are a hardy, versatile veg and a good choice for any plot. As the easiest to grow out of the
Onion family, they do still require some attention but are generally untroubled by pests or diseases and do not need the same level of fertility in the soil as onions. An added bonus is that the thick stems are good at breaking up clay soil.
Soil & Growing Position
Leeks will tolerate most soils as long as it is not too compacted or water-logged. For optimum growing conditions, choose a sunny spot and dig thoroughly in the autumn/winter. Add in some manure if the soil has not been manured for a previous crop, leave rough over the winter and then level by treading down in the spring. Add in some general fertiliser 2 weeks prior to planting.
Sowing from Seed
Sow from mid March to mid April outdoors once the soil has warmed up. Sow thinly in rows 6" apart, at a half inch depth. Sow a late variety in June, transplant in July for cropping in April. Germination takes up to 18 days. Early varieties take around 30 weeks from sowing and lifting and later varieties take 45 weeks.
Growing On & Young Plants
Thin the seedlings to one and half inches and transplant in June once the seedlings reach around 8cm and are the thickness of a pencil. The ends of the roots and the tips of the leaves will need trimming, then plant 6" apart in rows 12" apart. Plant by using a dibber to create a hole 6" deep. Then drop in the plant, do not refill the hole with soil but instead fill the hole with water.
Crop Care
Water during dry spells, avoiding getting soil in the holes. Blanch the stems once the plants are well established, to lengthen the white part of the stem, by drawing dry soil up against the stems. Do this gradually in stages as the plants develop, adding extra height each time and stop earthing-up in late October. Avoid getting any soil inside the leaves as this will make the leeks gritty.
Feed the crop to thicken the stems but cease feeding by mid August.
Hoe to keep the weeds down.
Harvesting
Harvesting lasts around 6 months, beginning in late autumn and continuing through the winter. Leeks are very hardy and can be over wintered in the ground and dug up as required. Use a fork to carefully lift out the leeks, do not pull them out of the ground. Start harvesting from when the leeks are on the small side, as the bigger the get, the less flavour they have.
Onions,
Shallots and
Garlic
Onions can be grown from seed or from sets. The most popular method is by growing onion sets which are young bulbs which have been grown for planting. There are definite advantages over growing from seed as the crop matures quicker and unlike growing from seed, there are no risks of attack by onion fly who are attracted to the scent released when the seedlings are thinned out. However, seed is cheaper and there is a wider choice of varieties to choose from.
Shallots are effectively small, mild onions with a sweeter flavour which are harvested in the summer. Shallots are usually grown from sets and should be treated in virtually the same way as onions. If stored correctly, they can last for in excess of 8 months. If you are using sets and you are not planting them yet, store them in a cool and well-lit place. Open the packet and spread out the onions.
Soil & Growing Conditions
Choose a sunny spot with good drainage. Dig in autumn/winter, incorporating manure or compost. If your soil is acidic, add in lime. Rake in Growmore 2 weeks prior to planting. Firm the soil by treading and the rake to produce a fine tilth.
Sowing from Seed
There are two sowing periods for
onions, spring for an autumn crop or in mid August/early September for a June/July crop. Spring sowing can start as early as late February if the weather is mild and the soil workable and continues up to early April. Sow very thinly in a prepared seed bed, at a half inch depth in rows 9” apart, watering carefully if the soil is dry. Germination takes around 3 weeks.
Exhibition growers and those in particularly cold areas sow in January under glass, harden-off their plants during March for planting out in April. Sow a couple of seeds in a 15 cell tray and thin to one if both germinate. Keep these at a temperature of around 10 degrees (not much warmer otherwise they will bolt) until established then move out to a coldframe for hardening off before planting out in mid spring.
Japanese onions are sown in mid August for harvesting in late June whilst other varieties sown at this time will mature from late July. Japanese onions are sown thinly, 1” apart in rows 9” apart. Spring/salad onions are sown in March to July for a June to October harvest or in August for a March to May crop. They should be sown in rows 4” apart.
Planting Onion & Shallot Sets
Plant onion sets in mid March to mid April, spaced at 4”, in rows 9” apart, by gently pushing into the ground. Shallots should be planted earlier, mid February to mid March, spaced at 6” apart.
Planting Garlic
Separate the cloves from the garlic bulb and plant 2" deep and 6" apart. Water if the weather is dry and aside from that, there is little more to do until harvesting. Follow the same harvesting instructions as for onions.
Growing On & Young Plants
When the seedlings have straightened up, thin spring grown crops to 1 - 2” and then later to 4” apart. Water before lifting if the soil is dry, be careful when handling the seedlings and dispose of all the thinnings in order not to attract onion root fly. Onion and shallot sets begin to sprout within 2 weeks.
Japanese types only need thinning once, to 4” apart in the spring.
Salad onions are only thinned if necessary, to 1” apart.
Crop Care
Use netting to protect against birds and hoe regularly to keep the weeds at bay. Ensure any sets which have been lifted by birds or frosts are firmed back in. Watering is only necessary in dry weather. Autumn-sown crops should be fed in March with a liquid feed.
Harvesting
The harvesting period is July through to September. Onions from seed sown in August take 46 weeks while spring sown crops are ready in 22 weeks. Onions from sets take around 20 weeks. When the crop is ready, the foliage turns yellow and falls over. Leave for about 2 weeks, pick a dry day and then carefully lift with a fork. Any onions which are intended for storage must be dried first. This takes up to 3 weeks depending on the size of the onions and the conditions. Japanese types are not suitable for storing. Lay out the onions on trays and place outside in the sunshine (or inside if wet). Once dried, store in nets in a light and cool place and they should keep up till spring. Regularly inspect the onions during the drying and storing process for any rotting specimens which could affect the whole lot.
Shallots from sets are ready for lifting around 18 weeks after planting. Once the leaves turn yellow in July then lift and divide the bulb clusters. Prior to storing, remove any soil and brittle stems. Store in nets in a cool, dry place.
Salad onions are harvested between March and October. They are ready when the bulbs are between half and one inch across
