By Judymine
United Kingdom 
I have grown veg for many years. Gradually I get less and less produce. This year it is really bad. For example, my (home grown from seed) courgettes have a few leaves and the occasional flower which doesn't progress whereas the couple I gave away to a friend have had loads of veg already. Also my peas, beans etc. I am not a deep down gardener but have always happily produced many veg in the past. I dig in manure and compost every year. I plant my plants with extra compost in the trenches etc. What is going on? It is very dispiriting to spend time and trouble and nothing happens.
I have a problem with mare's tail and have not managed to get rid of it over 20 years, but in the past this has not affected my veg.
Any ideas please?
3 Aug, 2017
Answers
If you have been adding manure and compost for many years it may well be that you have turned the soil acidic. If you have not added lime then may I suggest that you buy a cheap soil testing kit and find out if you need to apply lime. Many vegetables prefer a slightly alkaline soil.
3 Aug, 2017
An over acidic soil is said to be 'sour' by the way.
3 Aug, 2017
It is difficult to pin point what the problem is but just try a few things. As regard the mare's tail, I don't think they are exhausting the nutrients in your garden. I would, for the moment, just pull them. Perhaps try and leave the manure and compost alone for a year and regarding your courgettes, grow them on a slight mound as the old gardening books suggested the when growing marrows.
3 Aug, 2017