Plants struggling this year

[bikermike]

Its a serious issue in the railfan community, there were hundreds of miles of narrow-guage track all over the irish peat bogs... won't somebody think of the trains...

immature compost is a problem as its a vicious cycle, it's bot good enough, so you pull the next batch through which hasn't had long enough, and so on.

the best thing for my composting was the local authority charging for green bin collection. I now have neighbours who are very keen for me to take their stuff.

[quanglewangle]

My problem with my home brewed compost is that it's not sterile. It gets hot enough to kill most pathogens and seeds but nowhere near all. I use it outside but I wouldn't trust it in the crowded humid conditions of greenhouse beds.

I've tried the steel sheet over a big fire method but it's a huge smelly faff and I'm still not sure it gets hot enough.

[bikermike]

Is it major problem? I use home-made compost in the gh (with a topping of bought) and I'll get the odd weed and rogue tomato, but not to a material amount.

my home compost is mostly kitchen waste, shredded paper and lawn clippings, so maybe that keeps weed seeds out of the cycle. My plot is weedier, but it's difficult to tell if that is the compost or stuff blown in.

[ameno]

I've never had any luck growing stuff in my home-made compost. Everything ends up looking yellow and sickly and barely growing.
After looking into it, I found that homemade compost is often pretty low in the major three nutrients, especially nitrogen (it does depend what ingredients you use, but mine is mostly kitchen waste, shredded paper and shredded woody prunings), so that's probably why mine is unsuitable as a potting medium. Homemade compost is always fairly high in micronutrients, though, even when it's low in the major ones.
So I just use mine as a mulch and a soil improver now.

[quanglewangle]

I used to sprinkle high nitrogen fertiliser on my compost heap and that really caused a heat-up. Can't buy ammonium nitrate any more - naughty people might use it for activities that would get us on a list for even discussing them.

Can't even buy nitric acid to make potassium nitrate from the wood ash from our boiler, for same reason I guess.

[Dynamo]

It depends heavily on the compost, and it's irresponsible to just sweepingly claim "peat-free compost is bad because..." when that really only applies to specific products, not peat-free compost in general.
Several of the Which best buys this year are peat-free, and have been for several years. You just need to know which are the good ones, and which are the ones to avoid. But the same is true of peat-based composts. Peat-based and peat-free composts are also among the worst scoring in Which Gardening's latest trials, so it's not even as if peat-based ones are more reliably good. It depends entirely on the specific product and formulation.

This is an interesting video made by Tony O'Neil where he tests ten different non peat composts and doesn't have a good word to say about any of them.

https://youtu.be/nztZ624qfWw

The way I see it, I'm all in favour of non peat composts and I would use them all the time, but I think the industry as a whole needs to get its act together and start producing better quality stuff.

[ameno]

This is an interesting video made by Tony O'Neil where he tests ten different non peat composts and doesn't have a good word to say about any of them.

https://youtu.be/nztZ624qfWw

The way I see it, I'm all in favour of non peat composts and I would use them all the time, but I think the industry as a whole needs to get its act together and start producing better quality stuff.

As far as I could tell, he seems mostly to be making a whole load of superficial judgements based simply on what the compost feels like, looks like, or what ingredients are in it. He didn't actually test any of the composts at all. He can say what he likes about their appearance or texture or whatever, but at the end of the day actual performance is really the only factor which actually matters (well, that and price).

Which Gardening actually test composts, in the same conditions for all compost brands on test, judging the actual performance of the composts on test with different types of plants and based on multiple variables.
In the simplest terms, the composts which give the best germination and strongest seedling growth get the best score for Seed compost; the ones which give the strongest growth and healthiest looking plants for growing on get the best Young Plants score; and the ones which give the largest, strongest plants with the best display of flowers and the best veg crop (usually potatoes) get the best Container compost score.
I'll trust them over some guy on Youtube who doesn't seem to even actually test the composts he is dismissing.

[Penellype]

With regard to home made compost, I use mine (from the hotbin) to grow potatoes in buckets, which it does very well with a handful of bfb added at planting time. The potatoes don't mind the chunky bits and by the time they are harvested the sticky consistency of the fresh compost has changed to something that can be sieved to get the larger lumps out - these then go back in the hotbin as "bulking agent" to create air gaps and aid decomposition. I then use the sieved compost for other crops such as carrots.

My problem with bringing home made compost indoors to use for seeds etc is that it is full of creepy-crawlies. I've no objection to these outdoors but I don't want them in the house! I therefore need some input of bought compost and like others on this thread, I am really struggling this year. The composts I can find seem to fall into 2 categories - peaty types which are fine and soft but seem to act like blotting paper, soaking up so much water that they rot the seedlings and grow a layer of green algae on the top regardless of how carefully they are watered. This then stunts or stops growth. The other sort (mostly peat free) are fibrous and chunky, impossible to sieve and not at all suitable for sowing small seeds (I pulled a 4 inch piece of wood out of a bag of Miracle Gro along with several pieces of plastic). I also find that they hold nearly no water and don't have much capillary action, so plants on a self watering tray can dry out even when the tray is full. Seedlings in these composts seem to show signs of nutrient deficiency faster, probably due to large amounts of unrotted wood etc as mentioned earlier.

I don't know what to do about this. I have tried 6 different composts this year (2 of which were only purchased recently and are of the peaty variety) and I have resorted to mixing one of each sort together in the hope that I will get the better qualities of each and not the worst of both.

[peanut]

My problem with bringing home made compost indoors to use for seeds etc is that it is full of creepy-crawlies. I've no objection to these outdoors but I don't want them in the house!

This struck a chord with me. After having all my plants in and out of the house for what seemed like an eternity this year, I kept finding snail or slug trails across the carpet and on the table where they started eating my newly germinated seedlings
Finally I had enough and as a last resort I actually sprinkled slug pellets over my carpet and table!
It worked a treat
But I never, in a million years, dreamt I would ever have to do that.

[Dynamo]

Further to my post earlier post I decided to do a little experiment with peat free compost seed compost and John Innes seed compost. Here are the results so far.

The first picture is cabbage, and the second is lettuce.

The first 6 pots in the left hand tray is peat free seed and cutting compost. The 6 pots in the 2nd tray have peat free compost but I used home made plant food. I'm going to overdose them on the plant food to see if there's a reaction. The 6 pots in the 3rd tray from the left have peat free compost but I've fed them with Miracle Grow fertiliser. The 6 pots in the right hand tray used John Innes seed compost which has some peat in it, but I've used no fertiliser in it so far.

Make of the photos what you will.

[ameno]

Cheap composts sadly often don't have adequate fertiliser added to them (as your results show, since the ones you fed are doing reasonably well), but that goes for both peat-free and peat-based composts (in fact it can potentially be worse in cheap peat-based composts, as peat itself is naturally completely devoid of nutrient, and so is entirely depended on the fertiliser added to it before bagging).

Old compost also often has nutrient issues, as the nutrients can wash out of it if left in the rain, or break down into forms the plants can't absorb if left too long in sunlight. That's why you should always buy fresh composts every year and never use leftovers from last year for seeds or young plants (it should still be fine for containers or as a soil improver), and also always buy new stock when you buy compost, not old leftover stuff.

[Babru]

Further to my post earlier post I decided to do a little experiment with peat free compost seed compost and John Innes seed compost. Here are the results so far.

The first picture is cabbage, and the second is lettuce.

The first 6 pots in the left hand tray is peat free seed and cutting compost. The 6 pots in the 2nd tray have peat free compost but I used home made plant food. I'm going to overdose them on the plant food to see if there's a reaction. The 6 pots in the 3rd tray from the left have peat free compost but I've fed them with Miracle Grow fertiliser. The 6 pots in the right hand tray used John Innes seed compost which has some peat in it, but I've used no fertiliser in it so far.

Make of the photos what you will.

This is very, very interesting dynamo. Thanks for sharing.

I'm thinking that once peat free is mandatory I'll check out Which each year and go with their recommendations (I should be able to get it in the library). My home made compost makes a fine mulch, but not good enough for seed sowing etc.

I hope the manufacturers get their act together, otherwise many budding gardeners will turn away from growing because they get terrible results.

[Jungle Jane]

Old compost also often has nutrient issues, as the nutrients can wash out of it if left in the rain, or break down into forms the plants can't absorb if left too long in sunlight. That's why you should always buy fresh composts every year and never use leftovers from last year for seeds or young plants (it should still be fine for containers or as a soil improver), and also always buy new stock when you buy compost, not old leftover stuff.

You can add BFB to old compost to give nutrients. I always re-use old nutrient depleted compost,liquid fertiliser gives them some nutrient straight away,BFB can be used as a slow release fertiliser. Never say never…