Feeding plants

Posted: Monday 23 July 2012
by Adam Pasco

Take a closer look at the leaves of plants and their colour will tell you whether the plant needs feeding or not.

Close-up of Adam Pasco examining a leaf with interveinal chlorosis

I'm starting to feel quite sorry for my garden plants. After months of relentless rain and waterlogged soil, temperatures have now soared as summer arrives at last. But I've started to notice a problem. Everything in the garden is looking rather pale. Instead of plants carrying glorious green leaves, many are pale yellow or event slightly mottled.

It's not diseases that I'm worried about, although I'm certain that blight will soon be flourishing in these warm and humid conditions as it devastates potatoes and outdoor tomatoes. No, it's plant nutrition that concerns me. While some rain is welcome, as water drains down through the soil it carries away with it any soluble nutrients, washing them deep down out of reach of plant roots.

Nitrogen is a major nutrient needed by plants to produce healthy green leaves and shoots, and nitrogen is also a very soluble nutrient. Week after week of rain has been washing away nitrogen and other nutrients, causing foliage to turn pale and yellow.

My lawn looks very pale, as do many border and bedding plants. The nasturtiums have luscious large leaves, but all have pale blotches. Runner beans should be able to produce their own nitrogen in their roots, thanks to a symbiotic relationship they have with a beneficial bacteria living in root nodules, but even they are looking pale. And some of my apple trees show signs of interveinal chlorosis, where pale patches develop between green veins.

Take a closer look at the leaves of plants and their colour will tell you whether the plant needs feeding or not. In my garden it's time to put something back, and that means getting out with solutions of liquid feed to watering round each plant. I'll be doing the same with my lawn and crops.

Granular and powdered fertilisers are available to apply to the soil surface, but these need rain to dilute them before they'll start working, and I'm not about to ask for more rain.

So the most important job for the week ahead is feeding, and although this will take some time at least it's a job you can do while enjoying the sunshine. Just remember to wear a sun hat!

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Abby2 26/07/2012 at 21:52

Phew, it's not just my garden then! Was starting to get quite worried about the look of some of my plants. Will keep up with the feeding this week then - let's hope there is enough time to get around them all before the rain starts again!

Zoomer44 26/07/2012 at 22:03

Bring on some dry weather and sunshine. The leaves on my runner and french beans are begining to go yellow. Good advise, will start feeding stuff planted out with a good dose of liquid feed.

higgy50 31/07/2012 at 00:09

Umm, interesting piece Adam. I have made some plant feed from stinging nettles for the first time this year but I'm now in a dilemma as to what to feed with it and how much & how often to feed??

Anyone else use stinging nettle feed successfully and can help me with my dilemma??




Sparklepinksunflower 31/07/2012 at 17:25

I have barely fed anything this year as the thoguht of adding more water on the the garden seemed silly. I have used a bit of granular feed but I love a bit of mirical grow on my pots. it really does make your plants grow twice as big.