Growing some plants under glass means you won't have any problems with bad weather and garden pests.
Organising your greenhouse
Organise your greenhouse to make the most of all the available space, so you can be more productive.
Having different zones is an effective way of organising space, plus you won't get mixed up with what's growing in the pots when you keep similar types together. You should also consider a potting area and a storage area for seeds, compost, plant pots and small gardening tools.
What plants are tolerant to heat?
When deciding what to grow, learn what plants are tolerant to heat. Generally speaking, certain varieties fare better than others in high temperatures. Some are almost impossible to grow in summer heat, no matter how hard you try.
Plants with large leaves, such as spinach and lettuce, often grow well in high temperatures and can withstand the sun's rays. Other summer favourites include strawberries, green beans, tomatoes, radishes, cucumber, peppers and beetroot. Try growing watermelon, or herbs such as parsley, sage, thyme and oregano.
Don't spend too much time deliberating what to plant in a greenhouse, as you can over-think things and that will make it far too complex. Choose a few different varieties of fruit, vegetables and flowers and concentrate on getting the environment right.
What to plant in July
July is a great month for planting seeds, as the air temperature and soil are ideal for growth. The long, hot days and good light level speeds up the germination process. This enables you to extend your planting season in the vegetable patch, while also boosting your stock of biennials, perennials and exotics. Remember that extra watering will be needed, especially in a heatwave.
Plenty of vegetable and flower seeds can be sown in July including foxgloves - a biennial that should flower the following spring. Other flowers to plant in July include delphiniums, forget-me-not, pansies and wallflowers.
You can also sow fast-growing crops like French beans, radish, carrots and soybeans. Lettuces and other leafy salad plants are easy to grow in summer. Sow the seeds in shallow pots and harvest young leaves when needed for cut-and-grow-again varieties.
July is the final month to successfully sow carrots for an autumn crop. Plant in pots of soil-based compost or in shallow drills of soil for the best results. You can also sow turnips, radishes and cabbages.
How often should I water greenhouse plants?
The key to successfully growing plants in a greenhouse is watering them sufficiently. Providing plenty of hydration in the summer months is vital. Have you ever asked yourself why is my plant wilting? The most likely answer is because you're not watering it enough.
Watering a wilting plant can revitalise it almost immediately, combating the negative effect of a high summer temperature. Tomatoes in particular need plenty of watering if they're growing in a greenhouse in summer. If you've ever forgotten to water them one morning, you'll see the negative effects only hours later, when they're likely to be wilting badly, with the leaves curling up.
Gardening experts recommend watering your greenhouse plants twice as much in summer as in winter. It's best to do this first thing in the morning, or later in the evening, when it's not as hot and sunny outside. This is because the plants absorb more of the water when the temperature is cooler.
How to control temperature in a greenhouse
What should you do if your greenhouse is too hot? This is an important question, since intense summer heat can be bad for your plants.
Allowing ventilation, such as keeping the door and windows open, can not only cool down the air temperature inside, but it will also allow for natural pollinators to visit your greenhouse to help your plants thrive.
A good ventilation system will include simple air vents to let cool air in and hot air out. It is inexpensive to provide strategic ventilation spots. You can have them in the roof vents and wall vents. Add fans and evaporative air coolers to help maintain a perfect temperature.
Try to be aware of any potential heat damage to your greenhouse plants by keeping an eye on the weather forecast. If there's going to be a heatwave, make sure you water them more often. Some plants may benefit from shade at the hottest part of the day, which is around noon and early afternoon.
If they seem to be wilting, despite your best efforts with the watering can, add some temporary shade cloth to the roof until the heatwave has passed.
Look after your summer plants well using our handy greenhouse tips and you'll be rewarded with a bumper crop of fresh fruit and veg, as well as some beautiful flowers that you can plant in the garden when they're big enough.