Tuesday, 2 November 2021

Is it worth using fertiliser in autumn?

 I had an interesting question arrive, this morning: (*Waves to Nicola - "Hi there!"*)  asking about the validity of adding fertilisers such as Growmore, when planting shrubs etc at this time of year, ie mid to late autumn.

Would fertilisers be wasted, was the question, bearing in mind that the plants are now entering their dormant phase.

My answer is yes.

I feel there is no point using expensive fertilisers at this end of the year, although I am perfectly prepared to dollop on any amount of home-made compost as a mulch - once I've done the weeding in that area, of course! 

The pelleted sort of fertiliser, as opposed to liquid feeds, does say on the pack that it is - in effect - heat activated, ie the chemicals are not released until the weather is warm enough. The idea being that you scatter the pellets, and then as the weather warms up, the plant starts to need more nutrients, and they are slowly released by the pellets. 

So in this case, you would think that it would be fine to add them to shrubs etc in autumn, and they'll just sit there until next spring, when they will be needed. 

I'm not sure, myself: I'd prefer to keep the pelleted product safe and dry in the shed until the following spring. 

So, personally, then,  I would plant shrubs, and wallflowers, in the normal way, without additional fertiliser: then in spring, when they start to show signs of life, I'd either scatter a fistful of pelleted product around their base and fork it in, lightly, or I'd water in some liquid feed. 

Talking of liquid fee, I think that applying it in autumn would definitely be a waste, as the weeds would take full advantage and gobble it all up, while our precious plants would turn their noses up, in disdain. 

I have to say, on a purely personal note, that I now prefer liquid feed to anything else, with liquid seaweed being top of my list. 

The reason?

Firstly, it's cheap to buy, and very, very concentrated: just one measure into a watering can, so it goes a long, long way.

Second, because it is a thick brown liquid, you can see the water go brown, even when diluted correctly into the watering can, so there is a feeling that the product is actually getting to the plants. Yes, this is purely psychological, and for all I know they add a concentrated brown dye to the product!! But it makes me feel that I am doing the right thing.

Thirdly, it's ecologically sound: it's not a mass of chemicals, produced artificially, processed into hard little pellets, with a massive packing factory etc etc. Rather, it's a natural product: it's sustainable, being made from fast-growing kelp, and the processing is merely cutting it, collecting it, boiling and evaporating it. Nice!

Then fourthly, and this is the real reason: the pelleted one, if used when potting on plants, tends to persist in the soil, ie the pellets give up their nutrients (we assume!) but you can still see the little round pellets for months and months: they lose their bright orange colour, and look just like snail eggs! 

Many is the time I've been re-potting something, turned it out of the pot, had a mad panic thinking it was full of snail eggs, then tried to crush them, found them to be hard, and realised that they are no more than exhausted Growmore pellets! 


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  1. Not gone off comfrey tea? I also have a supply of worm pee from my wormery. Never know if I am applying the right concentration. 1:20 dilution is my arbitrary benchmark.

    1. Hi Mal, Comfrey tea is good stuff, but liquid seaweed gets top ranking, mainly because I can cheat, and buy it!

      Anyone who's ever made comfrey tea - or nettle tea for that matter - will know how smelly it is!

      As for the wormery, yes, I tried it, but as you say, it's hard to know what the "right" concentration/dilution rate is.


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