Feuilles qui s’affaissent !!

looks like little to now amendments that help with drainage and aeration of soil. This will be a big part of what you see. are those sticky traps full of gnats? there you go ... the larva have probably decimated the roots. get some Bacillus thurgin-something or other (israelis subspecies) -- i can't spell it but there won't be any other bacteria for this function - "Bt(i)" in north america there is a Summit brand that sells mosquito bits and dunks -- one is for top dress and one is to float in a reservoir. You almost certainly have a simialr produce in your region. This stuff has been used on the world's food crops for decades if not a century at this point. mid-problem it will take 3 weeks to clear up. If you use it pre-emptively, you'll never have a gnat problem every again. I top dress it every 10 days from the start. The substrates we buy invariable come with pests.. this product will take care of anything that comes from larva in soil. adult gnats don't do damage.. the larva is the concern. they are annoying but they don't eat/damage anything important. keep the sticky traps up.. i still keep 1 up... it catches 1-3 gnats in 100 days while using Bti regularly.