Anyone else ever had a bad compost that kills your plants?

[SallyWD]

I went to Homebase just over a week ago and bought lots of bedding plants, a big expensive hydrangea and some organic multipurpose compost. I planted the plants in the ground and in pots and for a few days they all looked healthy and happy. They were in all in a good position (all in different positions but all equally sunny but not too sunny) and I watered them each day just to keep the soil moist. However after about 4 days every plant that I'd planted in the new compost went droopy! I watered them but they contibued to droop and have now all died. I'm certain it's the compost as I used another compost for some plants and they're all thriving.

It's such a shame. I spent over £50 on these plants and compost. It's always my favourite time of year when I start planting up the garden. I will complain to Homebase but I just wondered if anyone had experienced this before? It seems bizarre to me that a compost could actually kill plants. Even if it was poor quality compost you'd only expect the plants not to thrive. Every single plant has dropped dead!

I wonder if you have over watered the plants? Its much better giving them a good soak every 3 or 4 days rather than topping them up every day. Did the plants have much if a root ball on them when you planted them up and do the pots have drainage holes in them?

@bilbodog Thanks for your reply. I'm sure I didn't over water them as I'm really careful not to. I just wanted to keep the soil slightly moist. Some plants were planted in the ground and others in pots with drainage holes. I used an old compost on some plants and they're doing well. Every single plant I used the new compost on has died. I usually have quite green fingers and all my plants thrive so this is very strange.

Yes, compost could've been contaminated with weedkiller. Have you bought your compost recently?? Please talk to the seller.

I haven't had any experience with Homebase compost but Charles Dowding and the RHS have written about compost and manure being contaminated with the weed killer pyralid in the past.

I haven't had it personally, though I've had tomatoes do less well in some random old compost I had to use when I couldn't get any in lockdown.

Hydrangeas like ericaceous compost and/or a more acid and well-drained soil. Also lots of water. I don't have much luck with them as our soil is quite alkaline.

I think its blue hydrangeas that need ericacious compost - mine have always been blue or white and have lived for years in ordinary compost.

Thanks for your comments everyone. It's interesting to hear avout some composts being contaminated. I'll definitely mention it to Homebase. Maybe they've had other reports. It's not just my hydrangea that's died - everything has. Geraniums, snap dragons, salvia, lobelia etc.

Me, unfortunately! 2or 3 years ago, my big compost order was contaminated with aminopyralid. Absolutely gutting.

If you google it, you'll see that there is a tell-tale curling of the leaves. Does this match what you have?

It impacts most plant families, but not grasses so you would be OK using it for that, if you're growing any.

@TheSpottedZebra Yes the leaves are all curling! I think you've solved the mystery. Thank you.

Oh no, that is a shame.
It's devastating to plants-and to growers.

Ive had the same problem this year with homebase organic compost. It does not drainage very well and is over saturated with salts, as when i water the planters the water that comes out dries to a solid white hue on my patio, 70% of the plants I put in this stuff have died. Avoid organic compost at all costs.

I had this exact problem a couple of years ago with a batch of multi-purpose compost from a big DIY shed. It's SO frustrating when you've spent money on plants and compost only for it to all die. Turns out it's a known issue with some composts being contaminated with persistent herbicides (aminopyralid/clopyralid) - they don't break down in the composting process and basically nuke any broadleaf plants you grow in them. The RHS has written about it, and Charles Dowding has done videos showing the difference between good compost and contaminated stuff.

One thing that really helped me was doing the 'mustard seed test' before using a new batch - plant some fast-growing seeds (mustard cress or peas) in a pot of the compost and see if they germinate and grow normally within a week. If they look stunted or weird, you know the batch is dodgy before you put your expensive plants in it. I do this with every new bag now, especially the cheap bulk stuff. Homebase should definitely refund you if you take the batch number and receipt back - they've had enough complaints about this over the years that they know it's a thing.

@SleepyLondoner Ace tip about doing a trial run with the compost before using it on expensive plants.

I was aware of this compost issue and even so, I did get caught out with one bag of nasty stuff last year. Thinking back to when I used it, the compost didn't really smell quite right when I opened the bag.

Hi ive had the same problem with multipurpose compost from homebase. It was extremely smelly to the point the one tub in the garden made the garden smell like a pig farm. I potted a Fusia and a spider plant. Within two days the plants wilted and were completely destroyed by day 5. I took the compost back to Hombase but they were utterly disgusting in the way they treated the issue. They said there was no smell. Without a word of a lie it was rancid and Homebase didnt want to refund. Eventually the manager agreed to refund two bags of soil but not the plants. There is a real nasty smell to this batch. Looked ot up and they say the batch may have to much feed added or the sun turned the compost. Either way its extremely lethal to plants inside or out. I asked for a refund on the flowers but he refused. Im now taking it to head office as something is very wrong with the soil. They should have refunded the plant money because its their compost that killed it. Ivs been searching online to see if anyone else had the issue. Im so glad I came on here.