Aphids and flies in peat free compost

[Viola]

Hi all,

I am new to this forum and writing out of sheer desperation as I can't find any help on the internet, the company that makes this product or Garden Organic.
My problem is and has been peat free compost. I like using it and have done so for the last 3 years, exclusively. I have grown chillies in the house but also house plants and every time they have been covered in aphids and little flies so badly that they could not be rescued and had to be binned. Last year I thought to try a reclaimed peat compost brand, very expensive but worth it.
The results were great, not a single aphid or fly.

The peat free brands I used were New Horizon and Miracle Grow. Both brands were the same, aphids and flies all over the plants.
My suspicion is that the eggs for the aphids and flies are present in the raw material that the peat free compost is made from and that it is not being heat sterilized properly to kill them.
I really, really want to use the peat free compost but I am not prepared to loose my plants to these pests. I am angry too as peat free costs extra and if you loose your plants, then it was a waste of money.
My big question is:HAVE ANY OTHER GARDENERS HAD THE SAME PROBLEM? I have searched high and low on the internet, not a single refernece. I have contacted Garden Organic (I am a member), no help either. I have contacted the manufacture of New Horizon Compost, they wrote back to explain about the flies, but nothing about the aphids.
The aphids are the more serious problem, as it is them who destroy my plants.

I am cross that these companies are so promoting their products and everywhere we are being told to use peat free, but I wonder how many customers have noticed this problem or have simply put it down to other factors. Have any of you put 2 and 2 together? It took me 2 years to realize that it was not me that was at fault. I thought initially that my pots weren't clean enough. But even when using brand new pots, the aphids and flies were there. We had to buy fly paper to catch the fllies in the house as they were a real nuisance.

Anyway, enough of a rant. I do hope that other people like me are just as desperate to get the manufacturers to change their ways.
I may have to contact Gardener's World to investigate further.
Thanks in advance for your replies.
Viola

[PLUMPUDDING]

All composts sold should be sterile - produced with enough heat to kill pathogens and insects etc. The Sciarid flies like wet compost, so perhaps you were keeping the compost a bit on the wet side, and this could be due to a denser texture in your peat free composts.

Since aphids fly about, they would most likely just have flown in and not be anything to do with the type of compost. Some years are worse than others. I bring a few ladybirds in to the greenhouse or conservatory and put them on any affected plants, and if there is a really big infestation I just rub the aphids off between thumb and finger.

[DiG]

Hi Viola and PP.

I used New Horizon peat free compost exclusively in 2010 and had a very severe infestation of aphids on my peppers which were raised in the conservatory. Last year I used a reduced peat compost (only because I couldn't get hold of peat free locally) and there was not an aphid to be seen. Whether this was due to the compost or just one of the usual fluctuations of pests that occurs each year i will never know.

I agree regarding the variation in quality of peat free composts; no bag I had was the same from what was ostensibly the same batch. We should certainly continue to lobby the manufacturers until they improve their standards.

Regards, Diane

[Viola]

All composts sold should be sterile - produced with enough heat to kill pathogens and insects etc. The Sciarid flies like wet compost, so perhaps you were keeping the compost a bit on the wet side, and this could be due to a denser texture in your peat free composts.

Since aphids fly about, they would most likely just have flown in and not be anything to do with the type of compost. Some years are worse than others. I bring a few ladybirds in to the greenhouse or conservatory and put them on any affected plants, and if there is a really big infestation I just rub the aphids off between thumb and finger.

I agree and I had the same suspicion that they had just flown in. BUT how come that with exactly the same conditions, window open occosiaonaly for fresh air to air the house etc. on the reclaimed peat there was not a single aphid that "flew" in from outside. The chilli plants are all on the bedroom window sill, facing south and now they look lovely, without the peat free compost. The best chillies ever and they kept going through the winter. I am not at all trying to knock peat free compost, just trying to find out if other people had the same experience. I think not even the manufacturers are fully aware of the problem and if they are, they should do something about it or people will use it even less. We need all the help we can get to get people away from using peat, and this probelm does not help.
Viola

[Viola]

Hi Viola and PP.

I used New Horizon peat free compost exclusively in 2010 and had a very severe infestation of aphids on my peppers which were raised in the conservatory. Last year I used a reduced peat compost (only because I couldn't get hold of peat free locally) and there was not an aphid to be seen. Whether this was due to the compost or just one of the usual fluctuations of pests that occurs each year i will never know.

I agree regarding the variation in quality of peat free composts; no bag I had was the same from what was ostensibly the same batch. We should certainly continue to lobby the manufacturers until they improve their standards.

Regards, Diane

There seems to be an emerging problem here. Anyone else had a similar exprience or are Diane and I the only ones so far?
I think many people still think it is the aphids that somehow land on the plants, like I used to, and this is simply very unlikely. I had grown chillies, basil and fuschias in peat based compost many years ago (before I knew about the problems with peat) and there were never any aphids compared to growing these same plants in peat free with aphids all over them. I know that peat is naturally sterile, but I think because it is made in such huge quantities, it is easier and more financially viable for the companies to sterlize it properly to kill any other insects eggs on the rest of the ingredients.
I would be very intersted to hear from others with such an experience as this is the only way that we can get the manufacturers to change the process.
Viola

[Johnboy]

Hi Viola,
A hearty welcome to the forum.
Until I had read your posting I had not heard anything regarding Aphids associated with Peat Free Compost.
Over the past year there has been a battle raging twixt peat free and peat usage and not once did the word aphid come up in the 'discussions.'
I'm afraid that I think it very unlikely that the compost would be carrying aphids but certainly Sciarid Fly chrysalis could well be contained within the peat free compost and this can be the case in peat.
With peat free compost a British Standard complete with Kite Mark is the only way to get any form of unification.
As Di has said that no two bags of peat free compost seem to be the same and there is a very vast difference across the range of peat free composts available which leaves the amateur and the professional gardener in a total quandary as to the best way to deal with what you have in one bag and the next bag being very different in texture and composition.
Dr Alan Knight, who is heading up the Sustainable Growing Media Task Force.
You can Email him direct at DEFRA secretariat: [email protected] and I should go to the very top for a start.
Dr Knight has written a letter published in this weeks Horticulture Week and quite frankly although he talks of a standard but it is not a British Standard and if you complained to trading standards they would dismiss you because without the proper standard there is nothing that they could really do.
The whole Peat/Peat Free affair has been so badly handled by DEFRA that in this case I do not believe them capable of doing the job properly.
I think it time that DEFRA had a very good overhaul and the deadwood dispensed with.
JB.

[Viola]

Hi Viola,
A hearty welcome to the forum.
Until I had read your posting I had not heard anything regarding Aphids associated with Peat Free Compost.
Over the past year there has been a battle raging twixt peat free and peat usage and not once did the word aphid come up in the 'discussions.'
I'm afraid that I think it very unlikely that the compost would be carrying aphids but certainly Sciarid Fly chrysalis could well be contained within the peat free compost and this can be the case in peat.
With peat free compost a British Standard complete with Kite Mark is the only way to get any form of unification.
As Di has said that no two bags of peat free compost seem to be the same and there is a very vast difference across the range of peat free composts available which leaves the amateur and the professional gardener in a total quandary as to the best way to deal with what you have in one bag and the next bag being very different in texture and composition.
Dr Alan Knight, who is heading up the Sustainable Growing Media Task Force.
You can Email him direct at DEFRA secretariat: [email protected] and I should go to the very top for a start.
Dr Knight has written a letter published in this weeks Horticulture Week and quite frankly although he talks of a standard but it is not a British Standard and if you complained to trading standards they would dismiss you because without the proper standard there is nothing that they could really do.
The whole Peat/Peat Free affair has been so badly handled by DEFRA that in this case I do not believe them capable of doing the job properly.
I think it time that DEFRA had a very good overhaul and the deadwood dispensed with.
JB.

Hi JB,

Thank you very much for the warm welcome. I had a feeling that the word "aphid" had not come up in connection with peat free compost, however, that does not mean they are not in there, in egg form.
I suspect it is due to lots of users who blame them landing on their plants instead of them hatching out of the compost. I was the same, I thought no way can this be, I did not want to put the blame on something that I had set my heart on to be ok and not ever consider it to be the source of the problem. But consider this: the raw materials that are being used for the compost - could they possibly come from council green waste that has not been heated thouroughly to destroy any insects/larvae/ eggs? The aphids can easily land on any plant material in these ingredients prior to composting and if the end product is not heated to a certain degree, then they survive.

The only way to be sure is to test the compost in the conditions that I have described (in the house, using clean pots) and have comparable peat based and peat free composts as part of the test. Also, this test must include plants that aphids love, like chillies, peppers, fuchsias, basil and other soft leaved plants (as my tomatoes and pelargoniums are unaffected, possibly due to their hairy leaves, which the aphids dislike).

It would not be the first time that anecdotal evidence from consumers is proving the experts and manufacturers wrong. Honestly, I am passionate about not using peat for all the obvious reasons, and I hope that our government and the manufacturers take this issue as serious as us gardeners.
Without any feedback from customers and consumers, there will be no change. I used New Horizon because it came out best in the Which trials, but I can't remember what plants they used in their trials and the compost is never from the same source anyway. But from my experience of using New Horizon (sourced from Harrod Horticultural) for 2 years and also the Miracle peat free (sourced from local garden centre), I had the same problem.

I shall take up your suggestion though and email Alan Knight, although I doubt that he can help. I think the pressure has to come form anecdotal evidence from us consumers.

I do remember the times during my childhood when there was no compost available at all to buy, as there was no garden centres back then. And we managed to grow everything just fine. And I must admit, I only use the peat free in the house but in the garden I always use my own home made compost for everything.

Thank you very much indeed to all those who replied. I wonder if KG would be intersted to take this up and ask the question in the magazine...
Just an idea.
Viola

[Colin_M]

I can't comment on compost being the source, but I find aphids infest many plants that I try to over-winter in our conservatory. Chillies suffer the worst, but many plants are affected.

Options I tried that work include:

Using natural predators. These are scarce in Jan/Feb and the companies that supply them normally quote later in Spring before they can despatch them. By then of course it's often warm enough to put plants out during the day, leave windows open etc to let local predators eat the aphids.

SB Plant Invigorator This does work and helped reduce the aphids in our conservatory this year.

Personally, I suspect previous populations of aphids have left eggs behind in our conservatory and they flourish when warmth and new green growth becomes available.

[AnitaB]

I have today sent this email to William-Sinclair the suppliers of the above compost. And await their comments etc. After reading posts - I also realise that I have also had very bad aphid problems also as reported by some people

"We have, for the last two spring/summers, been pestered with masses small black flies hatching on the compost used for our young vegetables grown for our garden and organic allotment. We grow in a both greenhouse and a porch with access to the house. These flies have swarmed on mass in the greenhouse and also have ended up as far as our bedrooms from the porch .

I have been spraying constantly with pyrethrum but it as been very difficult as they keep on hatching.

I have this year, started to suspect that it is the compost. Each year we have bought and used 1 bag New Horizon Organic Compost and also used the compost from 3 New Horizon Organic Growbags.

After finally getting on top of the hatching this year, I yesterday opened a New Horizon Growbag and found that it is alive with the flies

Needless to say that I will not be using this bag.

I am very disappointed with this. The compost was recommended by Which Gardening and we have used it exclusively . . I am not sure whether the problem originated also from the Compost bag, but I now have proof that it certainly did come from the compost in the growbags.

I am satisfied with the growing results and do not think these insect cause harm. However, they have caused us a great deal of trouble in the house and greenhouse given the numbers and speed with which they hatch.

Please let me have your comments on this"

[Colin Miles]

There have been many discussions on the merits or otherwise of Peat free composts - and comparative experiments carried out mainly by Alan Refail. If you search you will find this.

[alan refail]

There have been many discussions on the merits or otherwise of Peat free composts - and comparative experiments carried out mainly by Alan Refail. If you search you will find this.

viewtopic.php?f=4&t=9711
viewtopic.php?f=4&t=9797
viewtopic.php?f=4&t=9835
viewtopic.php?f=4&t=10072

[AnitaB]

Hi Viola

See my post lower down re the email I sent to the New Horizon company regarding our problem.

I have received NO Reply

AnitaB

[glallotments]

Hi Viola

See my post lower down re the email I sent to the New Horizon company regarding our problem.

I have received NO Reply

AnitaB

We have given up on New Horizon mainly due to inconsistent results but I do agree that it seems to attract lots of sciarid flies which are a particular problem when potting up houseplants! Our problem isn't due to us overwatering the flies seem to arrive no matter what. Also we have opened some bags of compost and found that it is soaking wet and unusable. We've also had fungal growth which the manufacturers claim is normal. I know fungus will grow on the rotting plant debris used in the mixture but like you expected the heat treatment to sterilise the bag.

It is really difficult to find a compost that has overall consistent results.