Supercharge Your Summer Garden: Here's How!

1 June 2024, written by Benedict Vanheems

With rapid growth and harvests taking off, there’s plenty to keep our green fingers and thumbs busy right now! So let me share some summer garden tasks to keep your garden moving along nicely. We’ll be harvesting something I’ve been looking forward to for weeks now, starting even more tasty crops, and checking in on my favorite summer staple – tomatoes!

Harvest Early Potatoes

But first, potatoes! Mine have been tantalizing me with their lush, verdant foliage for a while now. I started them in containers in my greenhouse at the tail-end of winter, and they’re now flowering. These are early season or first early potatoes, which are often ready within three months of planting. By starting them off in the greenhouse my first harvest should be a good two or three weeks ahead of my outdoor earlies. Nice!

To harvest container potatoes, first push your hand down into the potting mix and have a gentle feel around to check out what size the tubers are. If you’re happy with them, put down a tarpaulin and tip up the container. The potatoes won’t be massive, but they are just perfect for the very first salad potatoes of the new season. What an absolute treat!

Pick Fava Beans

Back in spring I planted fava beans, then last month put in place simple twine supports to stop plants flopping over. And already the first flowers are forming! Another few weeks and I’ll be picking my first beans to go with more of my sensational summer spuds.

Pinch out the very tops of your beans now to give black bean aphids fewer places to land and get settled. They prefer this tender growth, and by removing it, they’ll be less likely to set up shop on my beans. You can steam the tops as an extra bonus green.

When the pods start coming, inspect plants every few days then harvest the pods as they fill out to a nice, plump size. Be careful not to damage the plants as you harvest – either cut them off, or support the plant as you tug. Shell your pods then enjoy as soon as you can. This is another early summer treat to savor! I like the beans lightly boiled and served chilled as part of a springtime salad with mint, radishes, some crumbled feta and maybe a few toasted pine nuts to finish it all off… mmm, sounds good, doesn’t it?!

Asparagus ferns — Give asparagus plants a rest by allowing ferns to develop

Stop Harvesting Asparagus

Harvest asparagus by cleanly cutting away the spears about an inch below the soil surface, ideally when they reach around 6-8in (15-20cm), about ankle height, so they’re nice and tender. Midsummer is the last call for this delicacy, because plants now need a chance to recover.

It’s tempting to keep cutting more when there are still spears pushing through, but be strong, and let them grow on into feathery, ferny fronds. When they turn yellow in autumn, they can be cut back to ground level to tidy things up and remove any hiding places for pests like asparagus beetle. The ferns will help to recharge the crown of the plant ready for harvests to continue once again next spring.

Tying in a tomato plant — Keep tomatoes well-supported as they grow

Train Tomatoes and Cucumbers

Vining or indeterminate tomatoes need tying or weaving into their supports as they grow. Pinch out any side-shoots or suckers that form if you’re gardening in a cooler climate. That helps the plant to waste less energy growing stems, and instead focus on producing those irresistible fruits. In warm climates, tomatoes often fruit so willingly that pruning is unnecessary.

Cucumbers are treated much the same way. Weave the stems onto their supports, and remove side-shoots.

Protect Brassicas From Butterflies

Talking of moths, early in the season cabbage white butterflies or cabbage moths are few and far between, but as we tip into summer there are more of them about. Covering vulnerable brassica plants like broccoli and cauliflower is absolutely essential unless you want to spend ages picking off very hungry caterpillars!

Butterfly netting or insect mesh works well, but you need make sure the foliage of the plants doesn’t push against the netting or else the butterflies and moths can just lay their eggs through it. Secure the edges at ground level with bricks or boards so everything growing inside is safe.

Swiss chard — Brightly-colored chard will keep cropping when the weather cools

Plant Leafy Greens

Leafy greens like chard and kale are famously good for us, fueling our strength, better immunity, and general good looks – well, for some of us at least! Now is a good time to plant them, whether that’s using young plants you’ve raised from seed yourself, or plants bought from the garden center.

They should carry on cropping well into winter, possibly longer if you’re lucky. They are great for following on after earlier crops. To give the soil a bit of a boost, add a couple of buckets of mature garden compost and/or a little scattering of a balanced organic fertilizer such as chicken manure pellets. Plant chard about a foot (30cm) apart, and kale around 18in (45cm) apart. To finish, give them a good drink of water.

Because kale is a brassica, cover it with insect mesh to keep the butterflies, whitefly and other ne’er-do-wells at bay.

Lettuce — Don't waste any garden space - get fast-growing crops in the ground to replace spent crops

Start Succession Crops

It’s not just planting we can be doing now – there’s still plenty to sow, with the focus turning towards follow-on or succession crops. These include hardy winter brassicas like sprouting broccoli, a whole host of lovely maincrop roots for pulling up from autumn onwards, and fast-growing crops like lettuce. You can find more tips on what to sow now in this video.

Damping down hard surfaces in greenhouses will help raise humidity and moderate temperatures

Keep Greenhouses Cool

Another important job as temperatures really start to soar is keeping plants cool. Maintaining a cooler environment on hot days is important for plant health and to aid pollination – did you know, for example, that tomato pollination falls off a cliff above about 90°F (32°C)? This is mostly because the pollen dries out so much it becomes dust-like and doesn’t ‘stick’ onto the female stigma but just rolls off.

As well as keeping doors, windows and any vents open, you may also like to consider greenhouse shading. My greenhouse roof is just plain grubby, but I’m leaving on the grime until the autumn because it acts, rather conveniently, as shading. I’d like to say that’s by design rather than me being a touch lazy – but there you go!

Another tool in your cool-some armory is damping down, which is the term gardeners use for simply sploshing the wet stuff about. Pour water onto hard surfaces like paving. As it evaporates it not only raises humidity, it will also take the edge off the heat, helping plants to cope better. And – bonus – it also gives spider mites a tougher time of it because they much prefer a hot, dry environment.

Sow Basil

There’s one plant that really struggles in anything but Mediterranean-warm conditions – basil! It rarely thrives if sown too early in the season, but early this month is a prime time to get these sun-worshippers off the ground.

Probably the fastest and most reliable basil is your standard Genovese basil – great, of course, in pesto, pasta and the like. Sowing’s so simple – just sprinkle a tiny pinch of seeds across the surface of a pot, water gently and then, to keep the potting mix moist and warm, cover the pot with clear plastic. Remove the cover as soon as the seeds germinate. Keep them in the warm, but out of direct sunshine. After a couple of weeks, prick out the little seedlings and transfer them into their own pots.

Make another sowing early next month to ensure you have a succession of leaves to enjoy throughout the summer and early autumn. Lovely stuff!

Potting on peppers — Pot peppers on into larger containers once the roots fill its pot

Pot On Peppers

All types of peppers, whether sweet bell peppers or spicy chilies, love the warmth. Once the weather is reliably toasty you may find that sulking plants finally put on a much-welcomed growth spurt. Check they’ve got enough room in their pots to do their thing: support a pepper plant with your hand, turn the pots upside down and ease it out to and check the roots. If there’s a dense network of roots running close to the sides, they could probably do with more space.

Select a container that’s a little bigger, then repot using fresh potting mix. I like to blend all-purpose potting mix with coir, plus a little perlite for better drainage. Fill in this mix around the plant’s rootball as you go. Give it a drink to settle, then topping up the mix a touch if needed.

Remember peppers – and indeed all fruiting vegetables – will need regular feeding once they begin to flower so they have the energy to produce plenty of fruits. Use any liquid feed that is high in potassium, for instance a tomato feed.

We can’t be far from the first pickings of summer-fruiting favorites, making this a hugely exciting moment in the garden calendar. Share what you’re up to in your garden in the comments below!