Gardening: The magic of plant food
There are only a handful of subjects that make me sound like a cracked record as I tour around a garden in the company of its owner, and number one is plant food
Now, you might think, what’s all the fuss about, plant food must surely only be plant food, yes? Not so, and this is the reason why. When I come across a plant that has decided not to flower at its appropriate time, I ask two questions – when did you last prune this plant, and when was it last given any nourishment?
The significance of the first is plants will initiate their flower buds either in new stems produced that year, or if an early flowering plant, in the wood that it produced last year. Pruned at the wrong time, and you could remove all flowers for that year. With pruning, it’s not so much what you do, it’s when you do it.
However, if the answer was ‘not pruned’, then I move on to the second question ‘when did you feed it last?’ and here my little cracked record winds up. I explain the merits of each of the major plant nutrients (nitrogen, phosphorus and potassium – NPK for short), and how an imbalance of one can create problems, especially with flowering plants.
In a nutshell, nitrogen is basically the leaf builder, phosphorous the root builder and potassium is needed to initiate flower buds, flowers and then to set seed. There is no one universal plant food, they are all different. Manufacturers must express the NPK ratio on the side of the pack.
Here’s the science bit. If a plant food declares its NPK ratio as 5:5:5, you might think that’s good an even balance of each – answer, no. There’s a brand with an amazing name and it’s NPK ratio reads 22:7:14, and that, in my humble opinion, would produce lovely leaves but the flowering potential would be compromised. However, if the ratio read as 12:7:19, that would be the one to choose for all flowering plants.
And cracked record play not over yet, we move to the question of whether it’s better to offer plant food in liquid form or as granules.
Unless you can guarantee your soil is well hydrated at all times, I would choose granules to scatter around the base of each plant. Every time you water or it rains, the plant will have a little nourishment delivered and this will continue for at least six months. Spring is the perfect time to deliver this magic.
A liquid feed is a bit of a one hit wonder, and if the soil is dry, you can take it from me that little, if any, will hit the spot around the roots of your precious plants.
Valerie is a chartered horticulturist. As Auntie Planty she offers gardening problem solving sessions in your own garden, as well as a free monthly Gardening Club on Zoom.
auntieplanty.co.uk
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