@alltatup
thank you very much

From a grower as yourself, it means something

@gps420
I'm very happy you asked!! It's something you can do even to potted plants, altough it's much less useful i think. You can/should do that on your veggies as well!
It's not hay though, it's fresh cut grass that was spread over, and over time it dried. Hay isn't so good for that purpose. This is called mulching i think. (today I just added again grass, for the first time since it was planted)
It'll keep the moisture from evaporating, meaning the soil will stay moist for a VERY long time (15 days, didn't need to water. Actually I water to add molasses, I wouldn't need to water otherwise

)
BUT also, depending on the material used, it'll give nutrients to the ground. Green stuff will always contain nitrogen, so grass is the best, it contains mainly only nitrogen. Other plants can be used, like comfrey! That'll give nitrogen but also phosphorus and potassium it seems! Stinging nettle is also good, but it'll sting! haha So i make stinging nettle manure! Then add it to water (I stopped though, it's pH is too high (should add something to it to reduce pH, lazy)... Plants don't need it... So I just stopped).
You don't want to add nitrogen at all because you're in flowering? Add already dried stuff then.
It also contributes to life! Small insects will crawl about, spiders and such. It's good, it'll keep in check any infestation that could happen. So far so good, i'm just having a thrips problem right now. Planning on releasing lady bugs, even if it doesn't help much. Don't want to spray my flowering plants. Not taking any risks ^^
The thrips are not a real problem anyway, as long as its not too much. I like to let nature do its work... But I add a bit of protection myself, like mosquito nets (vs bees/pollination and butterfly for instance) and greenhouse for rain/concentration of sun rays.