Onion Pukekohe Long Keeper

🧅 Onion Grow Guide

Onion is a useful, space-efficient kitchen crop grown for its bulbs, stems, and green tops. It rewards patience, because it starts slowly from seed and needs steady care before it begins to swell into bulbs. Good onions come from fresh seed, fine soil, full sun, even moisture, careful weeding, and correct spacing. They dislike competition, heavy wet soil, and being rushed.

Onion seed is small and does not stay strong for as long as many other vegetable seeds, so old packets often germinate poorly. For the best results, use fresh seed and give young seedlings a protected start.

🌱 Sowing in Trays Versus Direct Sowing

Onions can be grown by direct sowing or by starting seed in trays, but tray sowing is usually the best method for home gardeners. Onion seedlings are thin, slow, and easily crowded by weeds. Raising them in trays gives better control over moisture, pests, and spacing, and it allows you to plant out only the strongest seedlings.

Sow seed into a fine seed-raising mix and cover very lightly. Keep the mix evenly moist but not waterlogged. Place the tray in bright light with good airflow. Once seedlings are tall enough to handle and have formed a small root system, they can be transplanted into prepared soil.

When transplanting, handle seedlings gently and avoid burying them too deeply. Plant them so the base sits just into the soil, with the green tops above the surface. Firm the soil lightly around the roots and water in well.

Direct sowing can work in a very fine, weed-free bed. Sow shallowly, keep the surface damp, and thin seedlings early. The main problem with direct sowing is that onion seedlings are slow and delicate, so weeds can overtake them quickly. Direct sowing is best only where the bed can be kept clean, moist, and undisturbed.

For most gardens, trays are the more reliable choice, especially if you want even rows, stronger seedlings, and better use of space.

💧 Seed Pre-Treatment

Onion seed does not need special pre-treatment. There is no need for chilling, scarifying, heat treatment, or soaking.

The most important thing is to use fresh seed. Onion seed loses strength faster than many common vegetables, so older seed may germinate unevenly or fail completely.

A short soak in clean water for a few hours can help hydrate older seed, but it is optional. If soaked, sow the seed straight away and do not let it dry out again. In most cases, fresh seed sown into moist seed-raising mix is the best approach.

🌏 Soil and Position

Onions grow best in loose, fertile, well-drained soil. The soil should be fine enough for small roots to spread easily and firm enough to support the developing bulbs. Heavy clay, compacted soil, or wet soil can lead to poor growth and rotting.

Before planting, improve the bed with compost or well-rotted organic matter. Avoid using fresh manure directly before planting, as it can encourage soft leafy growth and may increase disease problems. If the soil is acidic, onions may struggle, so a near-neutral soil is preferred.

The best position is full sun. Onions need strong light to grow sturdy leaves, and healthy leaves are what feed the bulb. Too much shade usually results in small bulbs, weak tops, and slow growth.

Onions also grow well in raised beds and containers. For pots, choose a wide container with good drainage. Depth is helpful, but width matters more if you want to grow several onions together. Use a quality potting mix and avoid letting the container dry out completely.

🪴 Care and Maintenance

Onions need steady care because they are poor competitors. Keep the bed weed-free, especially while seedlings are young. Pull weeds gently by hand so you do not disturb the shallow onion roots.

Water consistently so the soil stays lightly moist. Dry spells can slow growth and reduce bulb size, while waterlogged soil can cause rot. Once bulbs are close to maturity, reduce heavy watering so the outer skins can firm properly.

Feed onions with compost, worm castings, seaweed solution, or a balanced vegetable fertiliser. They need enough nutrients to build strong leaves early, but too much nitrogen late in growth can delay bulb ripening and produce soft bulbs that do not store well.

Do not mound soil over the bulbs. As onions swell, the tops of the bulbs may naturally sit partly above the soil. This is normal. Covering the bulbs too heavily can increase the risk of rot and poor skin formation.

If any plants send up flower stems too early, use those bulbs first. Once an onion flowers, the bulb usually becomes firmer in the centre and does not store as well.

🌼 Companion Planting Guide

Onions are excellent companions in mixed vegetable beds because their upright growth takes up little space. They are especially useful near crops that enjoy open airflow and do not heavily shade the ground.

Good companions include carrot, beetroot, lettuce, cabbage, broccoli, cauliflower, silverbeet, tomato, capsicum, strawberry, parsley, chamomile, dill, calendula, and marigold. Carrots and onions are often paired because they use space differently and can fit neatly into the same bed. Lettuce can grow nearby while onions are still small, provided it does not crowd them.

Flowers such as calendula, marigold, and alyssum help attract beneficial insects. Herbs such as dill and parsley can also support insect diversity when allowed to flower.

Avoid planting onions too close to peas, beans, and asparagus. These crops are generally not ideal companions for onions. Also avoid placing onions beside large spreading plants that shade them heavily, such as pumpkins, melons, or vigorous cucumbers.

🍽️ How to Harvest

Onions can be harvested at different stages. Young plants can be pulled early and used like spring onions. For full bulbs, wait until the bulbs are well formed and the tops begin to soften, bend, and dry naturally.

To harvest, loosen the soil gently with a fork and lift the bulbs rather than pulling hard. Pulling from firm soil can snap the tops or bruise the bulb.

After lifting, allow the bulbs to cure in a dry, airy, shaded place. Spread them in a single layer with good airflow. The outer skins should become papery and the necks should dry down before storage. Do not store onions that are bruised, soft, thick-necked, or damaged. Use those first.

Once cured, trim the roots and tops, or braid the tops if they are still flexible. Store bulbs in a cool, dry, airy place. Mesh bags, baskets, racks, or hanging bunches work well. Avoid sealed plastic bags, as trapped moisture encourages rot.

⚠️ Common Issues and Fixes

Issue	Likely Cause	Fix
Poor germination	Old seed, dry seed mix, or seed buried too deeply	Use fresh seed, sow shallowly, and keep evenly moist
Thin, weak seedlings	Not enough light, overcrowding, or poor nutrition	Provide bright light, thin seedlings, and use a gentle liquid feed
Seedlings falling over	Overwatering, poor airflow, or fungal disease	Improve airflow, avoid soggy mix, and water carefully
Small bulbs	Overcrowding, poor soil, too much shade, or weed competition	Space plants correctly, improve soil, grow in full sun, and weed often
Lots of leaves but poor bulbs	Too much nitrogen or unsuitable variety	Reduce high-nitrogen feeding and choose a region-suited variety
Bulbs rotting	Waterlogged soil, poor airflow, or bulbs buried too deeply	Improve drainage, space plants well, and avoid covering bulbs heavily
Flower stems forming early	Stress, temperature swings, or plants held too long before transplanting	Keep growth steady and use flowering bulbs first
Yellowing leaves	Natural ageing, nutrient shortage, water stress, or disease	Check soil moisture, feed gently, and remove badly affected plants
White patches or streaks on leaves	Thrips or sap-sucking pest damage	Hose leaves, improve plant health, use fine netting, and encourage beneficial insects
Leaf tips browning	Dry stress, salt build-up, wind, or nutrient imbalance	Water deeply, mulch lightly, and avoid overfeeding
Bulbs not storing well	Poor curing, thick necks, damage, or excess late nitrogen	Cure fully, handle gently, and use soft or damaged bulbs first

🌾 Seed Saving Guide

Onion seed saving takes patience because onions must complete their full life cycle before seed is produced. Choose the healthiest, strongest plants with good bulb shape, firm skins, strong growth, and good storage quality. Do not save seed from weak, diseased, soft, split, or early-flowering plants.

For seed saving, selected bulbs are usually lifted, cured, stored, then replanted so they can flower. Only the best bulbs should be kept for this purpose. This selection step is important because it helps maintain quality in future crops.

When replanted, the bulbs send up tall flower stalks topped with round flower heads. These flowers attract insects and need good airflow. Stake the stems if they become tall or bend in wind.

Allow the flower heads to mature on the plant until the seed capsules begin to dry and dark seeds become visible. Watch closely, because ripe onion seed can drop if left too long. Cut the drying flower heads and place them in a paper bag or on a tray in a dry, airy place to finish drying.

Once fully dry, rub the flower heads gently to release the black seeds. Separate the seed from dry flower pieces and chaff. Make sure the seed is completely dry before storage.

Store onion seed in a labelled envelope or jar in a cool, dry, dark place. Label it with the variety description and collection year. Because onion seed loses strength quickly, aim to use saved seed while it is still fresh.

Different onion varieties can cross if flowering close together. For more reliable seed, save seed from one onion type at a time, or keep flowering varieties well separated. Select from several strong plants rather than just one, as this helps maintain vigour.

🌿 Final Thoughts

Onions are not difficult, but they do ask for patience and attention to detail. The most important steps are using fresh seed, starting seedlings carefully, planting into fine fertile soil, keeping weeds down, watering evenly, and curing bulbs properly after harvest.

Tray sowing is usually the best method because onion seedlings are slow, fine, and easily overwhelmed in the garden. Direct sowing can work in clean, well-prepared beds, but trays give more reliable results for most growers.

With full sun, steady moisture, careful spacing, and good curing, onions become one of the most valuable crops in the kitchen garden.

---

---

Delivery Guarantee

We take great care to make sure your seeds arrive safely. If your order is lost or damaged in transit, we’ll happily send a replacement. Unfortunately, we can’t replace or refund orders that arrive later than the estimated delivery date, as delays can sometimes occur that are outside our control.

Please note that all dispatch and delivery times listed are estimates only. While we do our best to post promptly, delivery timeframes can vary due to postal service delays, weather events, or other unforeseen circumstances. We’re unable to take responsibility for any loss, damage, or cost that results from a late delivery.

An order is not considered missing until at least 20 business days have passed from the postage date. You’ll receive an email once your seeds have been posted, letting you know they’re on their way. If you don’t see it in your main inbox, please check your Spam or Promotions folders as sometimes our emails like to hide there.