Flowers form, look promising, yellow at the stem and drop. This is blossom drop, and in most gardens it’s a temperature problem rather than anything you did wrong.
✅ Quick Answer
- Is this usually serious?
- No, but it costs you a flush of fruit. It resolves when the weather does.
- Most common causes
- Night temperatures above roughly 21°C or below roughly 13°C
- Day temperatures above roughly 32°C
- Very high or very low humidity affecting pollen
- Water stress during flowering
- Excess nitrogen fertiliser
- Lack of pollination movement in still, sheltered spots
- First thing to check
- What were the overnight temperatures during the week the flowers formed?
- What NOT to do
- Don’t respond by fertilising harder. Nitrogen makes blossom drop worse.
👁 Look At Your Plant
Work through these before you decide what’s happening. Each one narrows it down.
- Do the flowers yellow at the joint and fall cleanly? That’s classic blossom drop.
- Was there a heatwave or an unseasonal cold snap about a week earlier?
- Is the plant in a still, enclosed courtyard or under cover with no breeze?
- Is the soil drying out badly between waterings?
- Is the plant huge, dark green and leafy? Too much nitrogen.
- Any tiny insects inside the flowers, or distorted buds? Consider thrips.
Most Likely Causes
Temperature outside the pollination window
Tomato pollen becomes unviable when nights stay above about 21°C or drop below about 13°C, and when days push past about 32°C. The flower can’t set fruit, so the plant abandons it. In much of Australia, mid-summer blossom drop is simply expected.
Humidity extremes
Very dry air makes pollen too dry to stick; very humid air makes it clump. Either way it doesn’t reach the stigma.
Water stress
A plant that dries out during flowering sheds flowers to protect itself. Consistency during the flowering period pays off directly in fruit.
Too much nitrogen
Tomatoes fed like lawns grow like lawns. Vegetative growth wins and flowers drop.
No movement for pollination
Tomatoes are self-fertile but need vibration — wind or a buzzing bee — to shake pollen loose. Indoor, greenhouse and very sheltered plants often need a hand.
🔧 What To Do Now
- Wait out the heat. Flowers that form once temperatures moderate will set normally.
- Shade plants through extreme afternoons with 30–50% shade cloth.
- Keep watering steady and deep, and mulch to hold moisture.
- Switch to a tomato-specific fertiliser lower in nitrogen and higher in potassium.
- Give flowering trusses a gentle flick or tap mid-morning to shake pollen loose, especially undercover.
- In hot regions, time plantings so the main flowering period avoids peak summer.
❌ What NOT To Do
- Don’t strip flowers or prune heavily in response.
- Don’t add more fertiliser as a reflex.
- Don’t spray insecticide unless you’ve actually identified an insect problem.
- Don’t give up on the plant — most set a solid crop later in the season.
💚 Can The Plant Recover?
Complete. Blossom drop affects the flowers open during the stressful period, not the plant. Expect fruit set to resume within one to two weeks of conditions improving.
Filed under Tomato Flower Problems. General gardening information — climate, soil, variety and local pests vary, so see our disclaimer.