Bunching Onion Ishikura

Basics

1. Capsicum (sweet/bell Capsicum) thrives in warm, sunny gardens.
2. Plant them in a spot with full sun (6+ hours) and rich, well-drained soil.
3. Prepare the bed by removing weeds and digging in plenty of compost or aged manure.
4. Use mulch around plants to retain moisture and suppress weeds.

Seed Trays vs Direct Sowing

Seedling Trays:

• Raise seeds in pots or trays filled with seedling mix, keeping them warm (16-35°C) and moist.
• This protected start speeds germination and gives plants a head start on weeds and weather.
• You’ll use fewer seeds and get sturdy seedlings for an earlier crop.
• The downside is extra effort and cost (pots, mix, heat source) and you must harden-off seedlings before planting out.

Direct Sowing:

• Plant seeds 3mm deep in the garden soil 50cm between plants, 60–100cm once it’s warm and frost-free.
• Direct sowing is simpler and cheaper (no trays or special mix), but germination is slower and more vulnerable to cold, pests or heavy rain.
• Capsicum seeds can take 1–3 weeks to sprout at 16–35°C.
• Ensure the soil stays evenly moist (not waterlogged) during this time.

In short: use trays if you want the best germination and an early start; sow direct if you prefer simplicity and have already warm conditions.

Planting and General Care

Timing & Spacing:

• Plant or transplant capsicum after all danger of frost has passed.
• In tropical/subtropical areas, Capsicums can even fruit year-round, but in cooler zones treat them as an annual summer crop.

Soil:

• Use well-drained, fertile soil rich in organic matter.
• Work in compost or aged manure before planting.
• Capsicums prefer a slightly acidic to neutral pH (~6.0–7.0).
• In pots, use at least ~40L per plant.

Watering:

• Water deeply and regularly, so the soil stays evenly moist.
• Check soil moisture by pushing a finger 4–5cm down; water when that layer is just dry.
• Water in the early morning or late afternoon to minimize stress.
• Avoid wetting the leaves, which can encourage fungal disease.
• Mulch around plants to keep roots cool and reduce evaporation.

Fertilising:

• If the soil was well-prepared, you may need little extra feed.
• Otherwise, apply a balanced (e.g. 10-10-10 NPK) slow-release fertilizer at planting.
• Once flowers and fruit start, give a liquid tomato or vegetable fertilizer every few weeks according to label directions.
• This supports heavy fruiting. Avoid excessive nitrogen late in the season, as it can reduce fruit set.

Staking & Pruning:

• Capsicum plants can get top-heavy with fruit. Stake or cage them when planting.
• A simple sturdy stake beside each plant works – gently tie the main stem (e.g. with soft string) as it grows.
• This prevents wind damage and keeps fruit off the ground.
• Remove any low or damaged leaves to improve air flow.
• Many gardeners also pinch out a few early flower buds when plants are young – this encourages stronger vegetative growth and heavier later yields.
• Overall, little pruning is needed beyond this.

Pest & Disease Management:

• Monitor plants for pests like aphids, caterpillars, slugs/snails, and chilli thrip.
• Hand-pick pests or use organic sprays if needed.
• Practice good hygiene: remove weeds and crop debris.
• Rotate capsicum/solanaceous crops to a different spot each year to reduce disease pressure.
• Common diseases include blossom-end rot (from inconsistent watering or low calcium) and fungal spots.
• Regular watering and mulch help prevent blossom-end rot.
• Crop rotation and not overcrowding plants also reduce problems.

Chilli Thrips: What They Are & How to Deal With Them

1. Chilli thrips (Scirtothrips dorsalis) are tiny, slender insects that can cause big problems in home veggie patches—especially for capsicum, chilli, eggplant, and tomato plants.
2. You might not see them easily (they’re less than 2mm long!), but the damage is easy to spot as leaves curl or look bronzed and scarred, buds drop off, and fruit can become deformed or scarred.
3. These pests feed by piercing plant tissue and sucking out the juices, which leads to silvery or brown patches on leaves and distorted growth.
4. They tend to hang out on the newest growth, flower buds, or the undersides of leaves—so grab a magnifying glass and check these spots first if your plants are looking stressed.

What You Can Do:

Prevention is key:

• Start clean – Avoid bringing in infested seedlings or cuttings.
• Attract beneficial bugs like lady beetles, lacewings, and predatory mites—they’ll help keep thrip numbers down.
• Plant flowers like alyssum, marigold, or dill nearby to draw in the good guys.

If they show up:

• Prune affected areas early to stop the spread.
• Hose them off gently with water to dislodge thrips from foliage.
• Apply insecticidal soap or horticultural oil, covering all leaf surfaces, especially underneath. Repeat weekly as needed.
• Rotate your crops each year to disrupt their lifecycle.

Tip: Thrips love hot, dry conditions—so keep your plants well-watered and mulched to reduce stress and deter infestations.

Companion Planting with Capsicum

Good companions:

• Herbs & Flowers: Basil, dill, parsley, coriander, chamomile and other aromatic herbs as they attract beneficial insects and may repel aphids or whiteflies. Garlic, onions, chives as their strong scent deters many pests. Marigolds, nasturtiums, borage, lavender as these flowers lure pollinators and trap pests (marigolds are famous for nematode control).
• Vegetables: Carrots, lettuce, spinach as they occupy shallow roots and don’t compete much with Capsicums. These can provide light ground cover under Capsicum plants. Tomatoes are sometimes planted alongside Capsicums (both like similar conditions) but be aware they share some pests/diseases so give them space and rotate beds regularly.
• Fruits: Strawberries and cucumbers have been noted as decent neighbours (shallow roots and shade from cucumber leaves can protect Capsicums).

Bad Companions

• Other heavy feeders or close relatives.
• Do not grow next to eggplants, potatoes or tomatoes in succession, as they share pests/diseases.
• Stay away from beans/peas and plants like fennel or dill, which can inhibit Capsicum growth.
• Squash and pumpkins (deep-rooted cucurbits) can out-compete Capsicums for nutrients.
• In short, pair Capsicums with light-feeders and pest-deterring plants, and keep them apart from other nightshades and big gourds.

Seed Saving

Saving your own Capsicum seeds is easy if you follow a few simple steps:

Select plants:

• Pick the healthiest plants with strong, typical fruit.
• If growing multiple types, isolate them (e.g. bag flowers or keep 20m+ apart) to prevent cross-pollination.

Harvest ripe fruits:

• Wait until Capsicums are fully ripe on the plant which is usually when they’ve changed to their final colour and just start to soften or wrinkle.
• Allowing fruits to over ripen a little ensures the seeds are mature.

Extract seeds:

• Cut the Capsicum in half and scoop or twist out the central core.
• Scrape out the seeds and remove as much of the inner flesh and pith as possible.
• Rinse the seeds in clean water to wash off any remaining pulp which helps them dry cleanly.

Dry seeds:

• Spread the seeds in a single layer on paper towels or a clean plate in a dry, shaded place.
• Let them dry completely over several days.
• They’re ready when you can crunch a seed in your fingers and it snaps rather than bends.
• Moisture is the enemy of seed storage, so make sure they feel fully dry.

Store seeds:

• Transfer the dried seeds to a paper envelope or small jar with a tight lid.
• Label with variety and date.
• Store in a cool, dark, dry spot (a refrigerator works well).
• Properly stored Capsicum seeds remain viable for about 3–4 years, so you’ll have plants for many seasons.

Starting Seeds in Trays 

Steps: 

1.Seed Trays: Use modular trays or small pots with a fine seed raising mix (not garden soil). 

2. Sowing: Plant 2–3 seeds per cell, 6mm deep. Lightly cover with mix. 

3. Germination: Keep moist and warm (18–25°C). Seeds sprout in 7–14 days. Use a heat mat if needed. 

4. Light: Place under grow lights or in a sunny window (12+ hours daily). Rotate trays to prevent leggy seedlings. 

5. Thinning: Once seedlings are 5cm tall, snip weaker ones, leaving 1 strong plant per cell. 

6. Hardening Off: 1–2 weeks before transplanting, gradually expose seedlings to outdoor conditions (start with 1 hour daily). 

7. Transplanting: When seedlings have 3–4 leaves (8–10 weeks old), plant 10–15cm apart in prepared beds. 

Pros: 

• Extends growing season in cooler zones. 
• Protects seedlings from pests/weather early on. 

Cons: 

• Requires more effort and equipment (lights, trays). 
• Risk of transplant shock if not hardened properly. 

Direct Sowing 

Steps: 

1. Soil Prep: Loosen soil to 30cm depth. Mix in compost or aged manure. Remove weeds. 

2. Sowing: 

• Create shallow furrows 1cm deep. 
• Sow seeds 2–3cm apart, then cover lightly with soil. 
• Water gently to avoid dislodging seeds. 

3. Spacing: Thin seedlings to 10–15cm apart when 5–8cm tall (use thinnings as green onions). 

4. Mulching: Apply straw or sugar cane mulch to retain moisture and suppress weeds. 

Pros: 

• Less labour intensive. 
• Avoids transplant shock. 

Cons: 

• Slower growth in cool soil. 
• Vulnerable to pests (e.g., slugs, birds) and weather extremes. 

Key Tips for Both Methods 

 Watering: Keep soil consistently moist until seedlings establish. Reduce watering as bulbs form to prevent rot. 

 Fertilising: Apply a nitrogen rich fertilizer (e.g., fish emulsion) every 2–3 weeks until bulbs swell, then switch to low nitrogen feed. 

 Pest Control: 

• Cover seedlings with insect mesh to deter onion flies. 
• Sprinkle diatomaceous earth around plants for grub prevention. 

 Thinning: Crucial for bulb development—crowded onions stay small. 

 Common Mistakes 

1. Overcrowding: Leads to competition for nutrients and stunted bulbs. 

2. Poor Drainage: Onions rot in waterlogged soil—ensure raised beds in wet climates. 

3. Late Transplanting: Seedlings older than 10 weeks struggle to adapt. 

Hacks 

 Tray Starter Hack:

• Trim seedling tops to 10cm tall if they become leggy. This strengthens stems. 

 Direct Sow Hack:

• Mix radish seeds with onion seeds—radishes mark rows and break soil crust for onion sprouts. 

Harvest 

 When:

• Tops yellow and fall over for full size onion. Lift bulbs gently. 
• Before bulb starts to swell for spring onions

 Curing:

• Dry in a shaded, ventilated area for 2–3 weeks. Store in mesh bags in cool (0–4°C), dark conditions. 

 Companion Planting Guide 

Plant With: 

• Carrots: Deter each other’s pests (onion/carrot flies). 
• Brassicas (cabbage, kale): Repel cabbage worms. 
• Tomatoes/Capsicums: Onions deter aphids and beetles. 
• Chamomile: Enhances onion flavour. 
• Marigolds: Suppress nematodes and beetles. 

Avoid: 

• Legumes (peas, beans): Compete for nutrients. 
• Asparagus: Inhibits growth. 
• Other alliums (garlic, leeks): Attract shared pests like onion maggots. 

 Seed Saving Guide 

1. Select Bulbs: Save seeds from large, disease free onions. 

2. Overwinter: Replant best bulbs in spring; onions flower in their second year. 

3. Isolate Varieties: Prevent crosspollination by spacing varieties 1 – 2km apart or bagging flower heads. 

4. Harvest Seeds: Let flower heads dry on plants. Shake seeds into a container and remove chaff. 

5. Storage: Keep in airtight containers in a cool, dry place. Seeds remain viable 1–2 years. 

Troubleshooting 

 Pests: Use neem oil for thrips or onion maggots. Interplant marigolds for nematode control. 

 Diseases: Rotate crops yearly to prevent fungal issues (e.g., downy mildew). Avoid overwatering. 

 Weeds: Mulch with straw or plant quick growing greens (lettuce, rocket) as living mulch.