Garden School:

Garden School:
Teaching this week: Nothing: my Trainee is on holiday!

Sunday, 13 October 2019

Feeding the plants

*bass voice* "Feed me!"
*me, nervously* "Does it have to be blood?"
*bass voice, imperiously* "FEED ME!"
*me, querulously* "Does it have to be mine?"

OK, we're not actually talking Little Shop of Horrors here, although blood does come in to it later, but today I received a question from regular reader Corine, asking for my take on the "when to feed the plants" debate.

"Hi, Corine!"  *waves enthusiastically*

Right, feeding plants: firstly, why do we feed our plants?

Ans: because we, the garden owners, force our plants into a very unnatural life: we prune them, we dead-head them, we restrict their growth, we shape them, we force them to flower and flower and flower until they are exhausted: at the same time, we often put them in "un-natural" habitats and/or microclimates, we expect them to perform for us, so in return we are duty bound to give them a helping hand.

This applies, at least double, to Things In Pots.

What do we feed them?

Ans: we give them concentrated nutrients.  I should stress, at this point, that feeding plants is no substitute for having good, healthy soil, but often our gardens (and this goes at least quadruple for Things in Pots) could really be described as the ultimate in intensive farming, because we like a garden which is packed with competing plants, and this stresses the soil.

So, our concentrated feed can be artificial fertilisers such as Growmore, or natural products such as pelleted chicken manure, powdered feed such as Fish, Blood (see, I said there would be blood later) & Bone, or liquid feeds such as Liquid Seaweed, which is my personal favourite, because it's organic, it doesn't stink as much as the others, and it's really concentrated, so a bottle lasts for ages. Plus it turns the water brown, so you can see that you have definitely added it to the water.

I'm not forgetting the truly organic feeds, such as mulching with home-made compost or farmyard manure, but today we're talking about "artificial" feeding, ie the concentrated stuff.

When do we feed them?

Aha, this is the crux of Corine's enquiry. It depends on what the plant is: is it a perennial, which dies down every winter? An annual, popping up from seed then disappearing forever? A bulb, with an underground storage system? A rhizome, with a partially underground storage system?

Easy one first: annuals. Feed them during their short, usually summer, lives. They need all the help they can get to grow, flower, set seed and die all within a few short months. As soon as they start to die down, don't waste money on feeding them, just collect the seeds for next year, and let them die back.

Perennials: feed them as they are starting to grow each year, and from time to time through their flowering season. (They should also get a non-concentrated feed in autumn, as they are dying down, in the form of mulching.)

Bulbs - daffodils, snowdrops, anything which goes completely dormant at some stage. These are the tricky ones, they need to be fed just after flowering, while the leaves are still green, from that point until they start dying down. Why? Because these plants use their bulbs as storage organs, and it's important that they refuel before they shut down for the winter. This autumn's fading foliage is what stocks them up for next season's flowers.

When you buy bulbs, which is usually in autumn,  you can see that they look like the onions we buy in the supermarket, ie a nice plump bulb, but virtually no roots. And if you lift your tulips or daffs each year, you will know that they come out of the ground with roots, but as they dry, the roots die off. They do this every year: they don't rely on their roots to feed them through the winter, they go completely dormant, and in spring they not only have to grow new roots AND new leaves, they are also expected to produce wonder flowers for us.

That's why we have to help them stock up after flowering: and I'm sure you've all been told that we have to leave the tulip/daffodil etc leaves to die down naturally, spoiling the look of the garden right into July (*mutter mutter*), and NOT cutting them off, otherwise we won't get flowers the following year. That's why: this year's energy collection fuels next year's flowers.

And that's why you will rarely find a recommendation to feed bulbs etc in spring, just as they are starting, even though it feels like the logical thing to do: if you do, you'll get fantastic leaves, but you won't necessarily get good flowers. To be more specific, if you didn't let them build up their reserves in the autumn, feeding them next spring won't help them produce flowers next year.

Rhizomes - such as Iris, bearded or otherwise - have good strong root structures, which feed them all year round, so they don't have the same problem of needing to be fed immediately after flowering: they benefit from feeding just as they are starting to grow, partly because Iris need their rhizomes to "bake" in the sun in the previous year, in order to get good flowers the following year: they don't need the extra nutrients, they need the sun. So for them, feeding them in spring and summer is the thing to do. Oh, and because they need the sun, they are the one plant that really does not enjoy being mulched in autumn: they like to be sat there on top of the soil, and if you smother them in mulch, they don't get the sun they need, and quite often the rhizomes will rot. So a concentrated feed in spring and summer is the best way to go.

How do we feed?

Pelleted chicken manure and powdery Fish, Blood & Bone are both sprinkled on the surface, although if using the latter, you should always gently scratch it into the soil, rather than leaving it sitting on the top. Two reasons why: it doesn't release the nutrients until it gets wet, so it's better to shove it down into the moist soil before it blows away on the breeze, and it smells irresistible to dogs, cats, foxes and vermin (all of which do eat, of course, fish, blood and bones), so you are likely to find them digging up the flower beds in an attempt to find the yummy dead bodies which their noses have - erroneously - told them are in the area.

Liquid feeds are super-easy, you just shove a capful of the concentrate into the watering can, and slosh it around, it doesn't matter if you get it on the leaves as well as on the soil.

Or, you can put it into a spray bottle and do proper foliar feeding: that's where you apply the diluted feed in a fine spray, direct onto the leaves.  This is a hugely un-natural way to feed plants, as every other method is basically soil-based, but ever since the 50s, when spray bottles were invented (*laughs*), we've been foliar feeding. Leaves are very good at absorbing nutrients, and a small amount can be very efficiently absorbed.

Of course, all the research which supports this theory has been done by the chemical companies who produce the concentrated feeds.... but it does actually work, and you can try this for yourself ("... children, just get some identical plants, a spray bottle, and some sticky-back plastic...") by spraying some plants, and surface-feeding others, and you will see the difference.

The great advantage of foliar feeding is that it's easy: just splash it on all over, and any leftovers sink into the soil, where some of the "goodness" will be absorbed by the roots.

Foliar feeding is particularly good for intensive growing, such as our crowded garden beds and borders, and for plants with stressed or limited soil, ie anything in a pot.

So there you have it: why we feed, how to do it, and when.

Any more questions, anyone? *laughs*

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