It’s time to dust off the tomatoes, pinch out the broad beans and dig up the potatoes. May is a glorious month that is rich with “grow your own” promise and also the month when the weather can go from one extreme to the other. Mini droughts, heat waves, sunburn to frostbite all in the same week. It’s hard to know what to expect! Mother Nature can play serious havoc for gardeners unless you are lucky enough to own a polytunnel, the weather really shouldn’t make much difference, your crops should be romping on!
Whilst it may be a shame to see the end of pretty spring flowers and blossom, the swallows have arrived and new exciting growth in the polytunnel promises a delicious, summer display!
Making the Most Of Your Polytunnel in May
Its official, salad season is upon us! Make the most of the space in your Polytunnel by sowing quick-growing crops, such as salads, between longer-term residents, such as brassicas while they’re establishing. Thin out direct-sown vegetables whilst still very small such as carrots, onions parsnips and beetroot seedlings then water the rows well. Always water along the row to settle the disturbed seedlings back in, once the job is completed.
What to Sow
- Any other salad leaves.
Make sure you sow them every few weeks, ensuring a constant supply throughout the summer.
Prevent Disease + Pests
Inspect your plants for pests and diseases – early prevention is easier than curing an infestation. Look out for
- blackfly on broad beans
- greenfly on peas, lettuce and cabbage
- root flies and carrot flies
- damage on brassicas (especially when the plants are small)
Spray the affected plants with soapy water (diluted washing up liquid) or squash the flies with your thumb and finger. Hang fly traps throughout the Polytunnel to monitor levels of whitefly and other pests or hang a clear freezer or carrier bag of water outside your door or inside your Polytunnel and it will/should scare flies away. I had never heard of using bags full of water to repel flies before and only after doing a little bit of Googling, it’s apparently quite common – Some claim water bags keep all kinds of flying insects away.
Keep it Cool
Polytunnels can get very hot when the sun is shining. Open the doors to allow cooler air to circulate and let pollinating insects inside. Open all vents on warm days to encourage good air flow and damp down your Poly Tunnel on hot days to increase humidity and deter red spider mites. Just remember our little mantra- Irrigate, ventilate, irrigate and ventilate a bit more.
It’s not just the plants you want that thrive at this time of year – weeds will be growing strongly, too. (Weeds are generally easiest to pull out when the soil is damp) Identify the weeds you want to remove, so you do not accidentally pull beneficial or desirable plants while you work.
1. Remember, don’t just think HOT. May can also bring frosts too, so check the forecasts in case you need to shut out an overnight cold snap.
2. Adequate watering is vital but too much can be bad news….especially if it causes rot near to ground level
3. Get your plants working for you. Climbing French Beans provide great shading for other plants like lettuce. And the marigolds planted last month will help protect tomatoes from white-fly.
4. Tie your tomatoes to supports or to strings suspended from crop bars. And remember to keep nipping off all those side shoots.
5. Continue pricking out and potting on seedlings and cuttings.
5. Put up poles/wigwams for runner and climbing French beans and support peas and broad beans before they become too tall.
6. Use a diary to keep track of which seeds you are sowing and when they were sown and planted out – it really helps later in the year.
May truly is one of the most exciting times in a polytunnel garden and there is so much going on! Make sure you make the most of the month and sow and grow a range of delicious produce. How are you getting on in your polytunnel this month? Let us know in the comments below.
Sean Barker is the MD of First Tunnels, and is enthusiastic about providing quality gardening supplies to gardeners across the UK