How to grow Rakkyo

How to grow Rakkyo - Introduction

• • Rakkyo is an important vegetable in the Orient and in the west is grown and used mainly by Orientals.

  • The plants do not produce seeds and are propagated by bulb division.

  • In mild climates, bulbs are planted in late summer, and the crop is harvested in midsummer of the following year.

  • Several small bulbs are obtained from each bulb planted.

  • Culture and exposure of plant parts is similar to that of bulb-set onions.

How to grow Rakkyo - Crop Rotation

• • Rakkyo is a member of the Onion family and should not be planted in soil that has borne a crop of any of the family members in at least the last three years.

How to grow Rakkyo - Companion planting

• • Rakyyo grows well with most plants, especially roses, carrots, beet and chamomile, but it inhibits the growth of legumes.

  • This plant is a bad companion for alfalfa, each species negatively affecting the other.

How to grow Rakkyo - Site and Soil

• • Prefers a sunny position in a light well-drained soil.

  • The plant prefers light (sandy) and medium (loamy) soils, and can grow in nutritionally poor soil.

  • The plant prefers acid, neutral and basic (alkaline) soils.

  • It cannot grow in the shade.

How to grow Rakkyo - Soil Preparation

• • It is best to prepare the soil well in advance of planting - December time is fine for spring planted onions, June is best for autumn planted rakkyo.

  • Dig the soil to 45cm (18in) deep, working in any organic matter available - remove any stones in the soil that you come across during the digging.

  • Just before planting, tread the soil down so that it is firm.

How to grow Rakkyo - Propagation

• The plants do not produce seeds and are propagated by bulb division.

• Sow the bulbs in spring in a cold frame.

• Prick out the seedlings into individual pots when they are large enough to handle – if you want to produce clumps more quickly then put three plants in each pot.

• Grow them on in the greenhouse for at least their first winter and plant them out into their permanent positions in spring once they are growing vigorously and are large enough.

How to grow Rakkyo - Planting out

• The bulbs should be planted fairly deeply.

How to grow Rakkyo - Care and Cultivation

• Plants often die-back in hot weather mid-summer, coming back into growth in late summer and flowering in the autumn.

• The flowers never set seed.

• Most members of this genus are intolerant of competition from other growing plants.

• Division in spring is very easy. The plants divide successfully at any time in the growing season and the divisions can be planted straight out into their permanent positions if required.

How to grow Rakkyo - Harvesting

• • There's never a time when onions aren't ready for harvesting.

  • They can be picked and eaten at any stage.

  • No matter how many onions you use during the season, though, it's nice to have a crop of big onions mature at the end of summer to store for the autumn and winter months.

When to harvest

• • You can always tell when onions have stopped growing. The leaves will lose their colour, weaken at the top of the bulb and flop over.

  • Each year a few new gardeners watch the leaves die and wonder, "What's wrong?" There's nothing wrong; it's Nature's plan. The leaves' job is done - they've put the last of their energy into the bulbs.

  • Let most of your onion tops fall over by themselves - maybe 80% or 90% of them - then bend over the rest of the tops.

  • Once they're down, leave the bulbs in the ground for another 10 days to two weeks to mature fully.

  • It's not good to leave the onions in the ground for longer than two weeks after the tops die because they become open to organisms that can cause rot in storage, or they might even start growing again.

  • Pull your onions up on a sunny day if you can, then let them sit in the sun for another day or so to dry (in hot climates this usually takes just a few hours).

  • This drying kills the root system at the bottom of each bulb. The roots will be like little brittle wires when they're dry.

  • Picking the right day to pull the onions can determine how well the onions will keep. If you harvest them after some rainy weather they'll have a lot more moisture in them and won't dry out as well.

How to grow Rakkyo - Storing and Preserving

• • After drying the onions in the open for a day or so, it's time to bring them under cover for a second, longer drying or "curing" process.

  • Some people cut the tops off the onions before curing, but that's not strictly necessary. However, if you do trim the top leaves, don't cut them any closer than 2.5cm (1") from the bulb. Otherwise the neck won't dry out, and the onion could rot in storage.

  • To cure the onions, spread them out in any warm, airy place out of the sun, such as under a carport. If you find you have too many onions for your available space, try spreading them out near the edge of your driveway, covering them with a light cotton (not plastic) sheet to provide shade. The sheet, held in place by stones along the edge, keeps the sun from burning the bulbs but still allows a lot of air circulation. Turn the bulbs a couple of times to promote even drying.

  • Heavy coverings like canvas or plastic trap moisture inside, so the onions will never get really dry. With the sheet system you won't have to worry about a few scattered rains. The sheets and the onions dry out rapidly together after a shower.

  • You don't want any wet spots on the onions when you put them in storage, so cure them really well. This can take two to three weeks. After curing them, hang the onions in mesh bags in your garage and dry them some more before putting them in your root cellar. It doesn't take this long in the South, but wherever you live, the longer you cure your onions, the better they'll keep.

Curing Basics

• • Here are the basics of curing:

    1. Sun dry for just a short time.

    2. Cure just the onions you'll store; separate the soft, young and thick-necked bulbs and use them first.

    3. Cure thoroughly in a warm, well-ventilated area away from direct sun.

    4. Don't crowd onions during curing; give them room to breathe.

    5. Onions are ready to store when the skins rattle and the roots are dry and wiry.

How to grow Rakkyo - Kitchen Notes

• • The edible parts of this plant are the flowers, leaves, root and seedpod.

  • The bulb can be used raw or cooked.

  • The bulb has an excellent crisp texture with a strong onion flavour, it can be 4 – 5cm (1½ - 2") in diameter, though it does not reach this size until the second or third year.

  • It contains about 3.1% protein, 0.12% fat, 18.3% soluble carbohydrate, 0.7% ash.

  • Leaves can be used raw or cooked.

  • Flowers and young seedpods can be eaten raw, and used as a garnish on salads.