By June and July the allotment should be in full swing. Tomatoes are setting fruit, cucumbers are climbing away, courgettes are producing faster than most of us can eat them and the salad beds are providing regular harvests. Yet this is also the time of year when problems start appearing. A few yellowing leaves on a tomato plant. Cucumbers that suddenly stop growing. Lettuce that wilts despite regular watering. Plants that look healthy enough but simply aren’t producing the crops you’d expect.
Over the years I’ve learned that most summer growing problems aren’t caused by one single issue. More often it’s a combination of weather, watering, nutrition and soil health.
Before reaching for any product, I always start with the basics. Good watering, healthy soil, mulching and regular hoeing solve a surprising number of problems. For fruiting crops such as tomatoes, peppers and chillies, I tend to favour specialist feeds designed specifically for those crops.
Here are six common problems I’m seeing on allotments right now and how I tackle them.
1. Yellowing Tomato Leaves
Few things worry gardeners more than yellowing tomato leaves.
If it’s just the occasional lower leaf turning yellow, it’s usually nothing to worry about. Older leaves naturally age and die off as the plant grows. However, if the yellowing spreads upwards or affects large areas of the plant, it’s worth investigating.
The most common causes are inconsistent watering, nutrient deficiencies or plants struggling to access nutrients that are already present in the soil. Tomatoes dislike feast-and-famine watering. Allowing the compost or soil to dry out completely before flooding it again puts the plant under stress and can affect nutrient uptake.
My first step is always to improve watering consistency and apply a mulch around the base of the plants. In greenhouses and polytunnels, regular deep watering is generally better than frequent shallow watering.
For a free solution, homemade comfrey feed remains one of the best feeds available to allotment gardeners. Comfrey is naturally rich in nutrients, particularly potassium, making it ideal for fruiting crops such as tomatoes.
If you’ve never made it before, take a look at our guide to making your own comfrey feed.
Where tomato plants are looking pale, lacking vigour or struggling to maintain healthy growth during heavy fruit production, S-Chelate Protom can provide targeted nutrition specifically designed for tomatoes and other fruiting crops. Alongside potassium and trace elements, it also supplies calcium, which becomes increasingly important as fruits begin to develop.
For more tomato-growing advice, see my Tomato Growing Guide.
2. Blossom End Rot on Tomatoes and Peppers
One of the most frustrating problems at this time of year is blossom end rot. You’ll notice a dark brown or black sunken patch developing on the bottom of fruits. Many gardeners assume it’s a disease, but it’s actually caused by a calcium deficiency within the developing fruit.
The important thing to understand is that the soil often contains plenty of calcium. The problem is usually that inconsistent watering prevents the plant from moving enough calcium into the fruit as it develops.
The free solution is simple:
- Water consistently
- Mulch generously
- Avoid letting plants dry out completely
- Don’t overfeed with high-nitrogen fertilisers
Good moisture management prevents most cases of blossom end rot.
Where plants have a history of blossom end rot or are being grown intensively in containers and greenhouse borders, S-Chelate Protom can be particularly useful. Unlike general-purpose feeds, Protom was specifically developed for tomatoes and other fruiting crops, supplying calcium alongside a balanced nutrient package to support healthy fruit development.
Combined with consistent watering, it can help reduce the risk of calcium-related disorders during periods of rapid growth and heavy cropping.
3. Cucumbers That Simply Stop Growing
Cucumbers are among the fastest-growing crops on the plot when conditions are right. When conditions aren’t right, they can seem to come to a complete standstill.
The most common causes are lack of water, cold roots, nutrient shortages or sudden changes in growing conditions.
Cucumbers are thirsty plants. The fruits themselves are mostly water, so even short periods of drought can slow growth dramatically. Irregular watering can also result in bitter or misshapen fruits.
My first response is always to check moisture levels. Mulching around plants helps retain moisture, while watering at the base of the plant encourages strong root growth. A homemade comfrey feed can provide an excellent boost once flowering and fruiting begin.
Where plants appear healthy but growth remains slow, S-Chelate 12 Star can help provide a broad range of nutrients and trace elements needed to support rapid growth and fruit production.
If you’re growing cucumbers this year, you’ll find plenty more advice in my complete cucumber growing guide.
4. Wilting Lettuce and Leafy Crops
Nothing looks more dramatic than a bed of lettuce collapsing during a warm afternoon. Fortunately, this doesn’t always mean the plants are dying. Often they recover fully overnight once temperatures fall. However, repeated wilting places plants under stress and can encourage bolting, particularly in lettuce, spinach and rocket.
The first line of defence is proper watering.
I prefer watering deeply and less often rather than applying a quick splash every evening. This encourages roots to travel deeper into the soil where moisture levels remain more stable.
Mulching also helps enormously.
One free technique that is often overlooked is regular hoeing. Breaking up the soil surface reduces moisture loss and helps keep water where it’s needed. The old saying that “one hoeing equals two waterings” still contains a good deal of truth.
If plants have been under prolonged stress, a balanced feed such as 12 Star can help support recovery and encourage fresh growth, but correcting moisture levels should always come first.
5. Plenty of Flowers, but Very Few Fruits
These are some of the common complaints at this stage of the season.
- Tomatoes flowering, but not setting fruit.
- Courgettes producing flower after flower, but little else.
- Peppers sitting stubbornly without developing properly.
Sometimes the weather is responsible. Cool nights, excessive heat or poor pollination can all reduce fruit set.
Greenhouse tomatoes often benefit from gently tapping flower trusses during warm afternoons to improve pollination. For courgettes and outdoor crops, encouraging pollinating insects can make a huge difference. Allowing a few flowers to bloom around the plot is often enough to increase pollinator activity significantly.
Nutritionally, fruiting plants require increasing amounts of potassium as flowering progresses.
This is another area where homemade comfrey feed excels. It’s one of the reasons generations of allotment holders have relied on it for tomatoes, peppers and cucumbers.
As tomatoes move from flowering into heavy fruit production, their nutritional demands increase significantly. S-Chelate Protom was designed specifically for this stage of growth, helping support continued flowering, fruit set and fruit development whilst maintaining healthy foliage and root growth.
6. Pale Growth and General Lack of Vigour
Sometimes plants don’t display a clear deficiency. They simply look tired. Growth slows. Leaves lose their rich green colour. Crops appear reluctant to put on new growth despite reasonable weather conditions.
Before assuming the problem is nutritional, I always look at the soil:
- Has it become compacted?
- Is it staying too wet?
- Has it dried out repeatedly?
- Are weeds competing for nutrients and moisture?
Addressing these underlying issues often solves the problem.
Adding compost, improving soil structure and keeping weeds under control remain some of the most effective actions any gardener can take. For free feeding, both comfrey and nettle feeds can provide valuable nutrients during periods of rapid growth.
However, where plants appear to be suffering from multiple minor deficiencies or trace element shortages, S-Chelate 12 Star can provide a broad spectrum of nutrients that help restore healthy growth and colour.
It’s often the trace elements that are overlooked, despite playing a vital role in photosynthesis, flowering and overall plant health.
Healthy Soil Comes First
Products such as S-Chelate Protom and 12 Star can certainly help support plants during periods of rapid growth, heavy cropping or environmental stress. However, they’re most effective when used alongside good gardening practice.
Regular hoeing, sensible watering, mulching, adding organic matter and making use of free homemade feeds such as comfrey tea will solve many common problems before they become serious.
Think of feeds and supplements as tools rather than magic bullets.
Healthy soil, healthy roots and consistent care remain the real secrets to productive allotments and vegetable gardens every summer.
