10 Things You Need to Know Before Getting Your First Polytunnel

Whether you're new to no dig or just considering a covered growing space, here’s a list of hard-earned insights directly from my latest polytunnel tour, filmed on a warm 2nd May.

1. It Gets Hot — Very Hot
   Even in early May, temps reached 43°C in the sun and 35°C in the shade.

   On warmer days, temperatures inside a polytunnel can spike quickly. Shade netting and wide door openings can help manage the heat.

2. You Can Track Seasonal Change Clearly
   Just 4 weeks ago, the tunnel was filled with winter salads.

   Watching seasonal changes inside the tunnel helps you anticipate planting cycles and crop transitions more confidently.

3. Don’t Pull Out Bolting Mustard Too Soon
   Letting mustard bolt can serve a purpose. See here and here.

   Bolting plants aren’t a waste — they can offer a great opportunity to collect seed and encourage genetic diversity for future crops.

4. A Tunnel is Perfect for Seed Saving
   Learn about ideal conditions for seed saving.

   Dry and protected from rain, a polytunnel allows precise control over watering — essential when producing viable seeds.

5. Some Seeds Are Worth Saving Every Year
   Especially onions like ‘Rose de Roscoff’.

   Some seeds, like onions, degrade quickly in storage. Saving your own ensures a fresh supply of the varieties you love.

6. You Can Still Plant in May
   It’s not too late to sow beans, basil and more.

   Don’t worry if you haven’t sown everything by April. There’s still a wide window in May to start fast-growing summer crops.

7. Observe Before You Act
   Let the plants guide you.

   Rather than rushing to clear plants, take time to observe their full lifecycle — it teaches you more about soil and plant health.

8. Use the Tunnel in All Seasons
   It’s a year-round tool.

   From autumn salads to spring onions, you can plan for continual harvests with the right timing and crop selection.

9. Save for Resilience
   Landrace mixing helps build future strength.

   Encouraging plants to adapt naturally to your soil and tunnel climate creates hardier, more productive crops long-term.

10. It Will Change How You Garden
    A tunnel gives you a new perspective on growing — faster, smarter, deeper.

    The tunnel becomes more than just a growing space — it’s a year-round lab for learning, experimenting, and improving your results.