foxy said:
I do wonder now if this was why I had such a poor strawberry crop last year...I did dig a lot of chicken manure into the bed, might have been a little too hot for them in retrospect
Yes, too much nitrogen makes strawberries grow big green leaves at the expense of fruit. Best to treat 'em mean, give well-drained compost, plenty of water when the berries are forming, and feed the plants with fertiliser which is high in potash rather than nitrogen, eg tomato food. Healthy productive strawberries should have pale green leaves, if they are dark green they're being overfed nitrogen.
Proper stable manure will add a lot of fertility to the soil because it incorporates straw soaked in urine, along with the horse droppings. However you have to be careful about what sort of straw has been used in the stable. I once dug in a huge amount of beautiful mature stable manure to my allotment and all sorts of things came up twisted and strange-looking. Apparently this is common where the straw comes from wheat which has been sprayed with whatever nasties farmers use on it, and so the best stable manure needs to include organic straw, if you can get it. I just had to wait for the effects to wear off on my plot - it took a year or so, and after all that hard work carting it and digging it in! Also the straw contains lots of wheat seeds which come up as weeds of course.
I agree with Chris that manure which is just picked up off the field is much less nutritious but is a good soil conditioner, and when soaked in a bag you get excellent liquid fertiliser - though I make this all year when I hose through the dirtied rubber chippings from the chicken run. However, any nitrogen-rich fertiliser is best used on plants which need to produce green leaves, like salads and cabbages, or plants at a stage of growth where they are producing their first leaves before fruiting, such as tomatoes in the stages before they set fruit. After that, tomatoes and any kind of berry or fruit-producing plant, tubers such as potatoes, and bulbs such as onions, and most flowering plants in bud, need less nitrogen and more potash, hence the balance in commercial tomato feed, which is useful for lots of things besides tomatoes. You can make your own high-potash fertiliser by soaking comfrey leaves in water - what a pong, but it's excellent. Or just add it to the compost heap, or the bottom of your potato or runner bean trenches.