Feeding plants in summer

David begins by explaining that, in summer, the main object of feeding plants is to promote flowering and fruiting, as well as toughening up foliage to resist pest and diseases. He runs through high-potash (potassium) feeds including liquid tomato fertiliser, which can benefit a wide range of other plants in borders, hanging baskets and containers.

Some plants, such as hardy bananas and palms (including Canary island date palm), need a high-nitrogen feed to promote strong, leafy growth. David outlines several options.

Then, he offers a solution for dealing with yellowing between leaf veins (also known as interveinal chlorosis), a symptom of magnesium deficiency.

Finally, David recommends a couple of general-purpose feeds including an easy, slow-release option that will keep working for six months.

Watch now, to find out how to give your plants a summer feed.

Feeding plants in summer: transcript

With the arrival of summer, your feeding regime can subtly change, away from encouraging plants into vigorous growth, and on to trying to encourage them to make more in the way of flowers and fruit and also to toughen up their foliage so that they resist pest and disease attack.

But there are a few things that you might still need to encourage into strong, vigorous growth. Things like hardy bananas and palms and anything with big, bold foliage that you've cut back early in the year and want it to make that surge of growth. For those things, then you would want to feed them with a high nitrogen feed, even in the summer, something like sulphate of ammonia, which is a granular formulation, scattered around the base of the plants and then watered in regularly. Or this vegetable and leafy plant feed. Again, high nitrogen, that's soluble. You dilute the powder into a watering can of water and then water it round the base of the plant. Both of those will encourage vigorous growth and nice dark green colouration.

But, for encouraging flowers and fruit and, as I said, to toughen up the foliage of plants, making them more pest and disease resistant, then high potash or potassium feeds are what you need. These really are in one basic form, tomato fertilisers. You will find other high potash feeds, but to be frank, a liquid tomato formulation is perfect, not just for tomatoes, but also for any fruiting plants, things like courgettes and beans. They will really benefit from potash, but also all your flowers and your annual plants, hanging baskets and containers. All will benefit from this liquid formulation, diluted again in water and then either applied direct to the compost or as a spray with a handheld sprayer. So, those are the basic feeds that you need to feed all through the summer.

But you may find that a few plants have a few nutrient requirements that make them produce odd growth. So, one thing in particular is, if a plant starts to show yellow speckles between the veins of the leaves, that's called interveinal chlorosis. And you can help your plants overcome that by applying Epsom salts. Epsom salts is magnesium sulphate, and that's simply put into water again, diluted in water and then applied around the base of the plants. So, this really benefits plants and helps them with taking up other nutrients that they need.

Then you'll also find some things that need a Maxicrop or a seaweed fertiliser. Really, these fertilisers contain a whole range of different micronutrients that are really beneficial to plants, things like boron and iron, that sometimes plants just don't really grow very well. And this will give a plant a really good tonic in the summer.
Again, it's a liquid feed that will quickly be taken up into the plant and put right any of those little niggly problems. And, in the same way, you might want to apply some sequestered iron to things like rhododendrons, azaleas, camellias and magnolias. All those plants really love growing on an acidic soil and if your soil is slightly neutral or even alkaline, you'll find that the plants will very often go a slight yellow colour on the leaves and the veins look very pronounced on the whole leaf surface. And then they will really benefit from that iron tonic just to bring them back into health.

And then, if you really just want to make feeding as easy as possible, then you could use either of these two general purpose fertilisers. One, Growmore, which is a standard product across a whole range of different suppliers, is a national formulation that's balanced between equal parts of nitrogen, phosphate and potash (potassium) . And that will give the plants a balanced feed and just keep them growing well and flowering well. And then you'll also find the slow release granules that you can scatter around the plants and that will slowly release those nutrients into the soil, every time you water and keep the plants growing for a good six months. These slow release pellets can be applied every six months during the whole course of the growing season and then, that cuts down on the amount of feeding you need to do. So all in all, a quick recap on the feeding that you need to do during the summer to keep your garden looking great.