In The Greenhouse This April

April is when your greenhouse really comes into its own—things accelerate quickly, but conditions can still swing from chilly nights to very warm days. Managing that balance is the key. Here are the most important tips:

🌡️ 1. Control Temperature (Big Day–Night Swings!)

April weather is unpredictable.

• Ventilate on sunny days—open doors, vents, or windows
• Close everything up in late afternoon to trap heat overnight
• Aim to keep temperatures above ~5°C at night if possible

👉 A max-min thermometer helps you stay in control.

🌱 2. Sow Tender Crops Under Cover

Your greenhouse is perfect now for starting:

• Tomatoes
• Peppers
• Aubergines
• Cucumbers
• Courgettes

Sow in pots or trays and keep them warm and well-lit.

🌿 3. Prick Out Seedlings Early

Seedlings grow fast in April.

• Move them into individual pots once they have true leaves
• Handle by the leaves, not stems
• Use fresh compost to avoid nutrient shortages

💧 4. Water Carefully

This is where many people go wrong.

• Water in the morning, not evening
• Keep compost moist, not soggy
• Seedlings need consistent moisture, but roots need air too

👉 Overwatering + cool nights = disease risk.

🌬️ 5. Keep Air Moving

Still air encourages problems.

• Ventilate daily when weather allows
• Prevents mould, damping off, and mildew
• Helps strengthen young plants

☀️ 6. Maximise Light

Light levels are improving, but:

• Keep glass clean (inside and out if possible)
• Avoid overcrowding seedlings
• Rotate trays so plants grow evenly

🪴 7. Start Feeding (Lightly)

Once plants are established:

• Begin light feeding (especially tomatoes once growing strongly)
• Use a balanced liquid feed weekly
• Don’t feed tiny seedlings too early

🌦️ 8. Harden Off Plants Gradually

Towards the end of April:

• Start acclimatising plants to outdoor conditions
• Put them outside during the day, bring them in at night
• Do this over 7–10 days

👉 Essential before planting out in May.

🐛 9. Watch for Early Pests

Greenhouses can attract pests early in the season.

• Aphids on soft growth
• Whitefly
• Fungus gnats in damp compost

Check regularly and act quickly.

🧼 10. Keep It Clean & Organised

A tidy greenhouse = healthier plants.

• Remove dead leaves and debris
• Clean pots before reuse
• Space plants properly to reduce disease risk

🌿 Bonus Tip: Plan Your Space Now

Your greenhouse will fill up fast.

• Decide what stays in (e.g. tomatoes, cucumbers)
• Plan when other plants will move outside
• Use staging efficiently