Busting Common Gardening Myths

Introduction

Gardening is full of well-meaning advice. Some tips have been passed down through generations, others picked up at the allotment or online. While many of these ideas start with good intentions, not all of them stand up to modern growing knowledge.

At Premier Polytunnels, we believe the best results come from understanding how plants actually grow – so we’re busting the top 10 gardening myths and explaining what really helps plants thrive, whether you’re gardening at home, on an allotment, or growing under cover.

1. Banana peels are a quick fertiliser

Banana skins are often said to be rich in potassium, but when buried in soil they break down very slowly and can attract pests long before nutrients become available.

Better growing advice: Compost banana peels properly so nutrients are released in a form plants can absorb. Balanced feeds deliver far more reliable results.

2. Gardening should follow moon phases

Moon-phase gardening (or lunar planting) is a traditional part of gardening folklore, but plant growth is far more influenced by temperature, light levels, moisture, and soil conditions.

Better growing advice: Time sowing and planting based on the season, weather patterns, and soil temperature – especially when growing in a polytunnel where conditions are more predictable.

3. Coffee grounds instantly improve soil

Coffee grounds are often praised as a soil improver, but fresh grounds can compact soil and affect pH levels if used incorrectly. 

Better growing advice: Add used coffee grounds to your compost heap so they break down slowly and improve soil structure over time.

4. Plants need watering every day in summer

Frequent shallow watering encourages weak root systems and increases water loss through evaporation.

What works better: Water deeply and less often to encourage strong roots. Polytunnel growing also helps to improve moisture levels by putting you in control of how much water your plants receive.

5. More fertiliser means faster growth

It’s easy to think feeding more will give better results, but over-feeding plants often results in lush leaves but fewer flowers or fruits – and can damage roots.

Better growing advice: Feed little and often, following plant-specific feeding guidance for steady, healthy growth.

6. Eggshells prevent blossom end rot

Eggshells take a long time to break down and don’t address the real cause of blossom end rot.

Better growing advice: Blossom end rot is usually caused by irregular watering. Keep moisture levels consistent, especially for tomatoes, peppers, and courgettes. 

7. Milk spray cures plant diseases

Milk sprays are sometimes suggested for fungal problems, but results are inconsistent and can create unwanted residue on leaves.

What works better: Good airflow, correct spacing, and clean growing conditions – all of which are easier to control in a well-ventilated polytunnel.

8. Weeds mean poor soil

Many weeds thrive in fertile soil and can actually indicate good growing conditions.

Better growing advice: Remove weeds early to reduce competition with crops and use them as indicators of soil health.

9. You can’t grow vegetables all year in the UK

The traditional outdoor growing season may be limited, but that doesn’t mean gardening has to stop.

Better growing advice: Polytunnels extend the growing season, allowing gardeners to grow winter salads, start seedlings earlier, and harvest for longer.

10. Gardening myths should be ignored completely

Some gardening myths are rooted in years of observation – they just lack modern explanation.

Better growing advice: Combine traditional knowledge with research-backed techniques and your own real-world growing experience.

Bonus myth – Polytunnels blow away in the first gust of wind 

Many people assume polytunnels are flimsy plastic greenhouses that won’t survive strong winds or need to have the cover removed each winter. In reality, that’s largely based on experiences with cheap, poorly anchored polytunnel kits.

Better growing advice: A properly constructed, well-anchored polytunnel with a tensioned polythene cover is designed to withstand British weather year-round. Commercial growers use them through winter without removing the cover – when installed correctly, there’s no need to strip them down. Well-made and well-secured polytunnels are designed to cope with wind and winter conditions just fine.

Grow Smarter With Premier Polytunnels

Successful gardening isn’t about shortcuts or old folklore fixes – it’s about understanding your plants and giving them the right growing environment to succeed. Healthy soil, consistent watering, good airflow, and protection from the elements all play a part.

A Premier Polytunnel gives you greater control over temperature, moisture, and growing seasons, helping you grow more reliably, for longer, and with better results – whatever the British weather brings.

If you’re ready to take the guesswork out of gardening and make the most of your growing space, explore our range of UK-made polytunnels and discover how much more your garden or allotment can produce.