Making new beds from lawn

Hi I'm new to the gardening game and have just begun to convert a large portion of my garden into beds to grow veg & flowers. So far I've managed to dig up and turn over a portion of the plot. I've dug in some horse manure from b & q, but some leaf mulch on top (found in the park) and covered it in polythene. The rest of the ground I intend to convert has been sprayed with roundup and, when the weather improves a little, I plan to dig in the same organic matter and cover. My question is, will the horse manure (bagged and sold by b & q) be suitably 'well rotted' to be able to grow seedlings in? I've been warned that it could burn the leaves and roots. Also, do you think I should spray the ground with something to kill any baddies which may be lurking in the soil? I'm a complete novice, so any advice would be gratefully received. Thanks

Hi Kate

i'd hold off with the chemicals. Too early for round up, it needs growing leaves to work on. Chemicals that kill baddies fill goodies as well. See what you've got before you kill it.

Bags of B&Q horse maure should be fine, they'll add some bulk. Not sure about the polythene, I'd be inclined to leave for weather to work on but others may have other ideas. It's a late spring, you've done well to get started.

Hello Kate,all i can say it that I dug up a lot of the lawn for beds last year and I did very little in improving the soil at that point and my plants did really well.

I wouldn't spray any areas, there maybe some good things growing as well. I do use weedkilller, i tend to paint it on selective invastive  weeds later in the year. I think these chemicals can have a longer term effect in the soil which affect the plants.

Just dug up some front lawn for a shrub border, solid clay so have to add compost etc to break it up a bit. Fortunately this atricious weather will help. Will then add horse manure mix that I get in bags locally.

Cookingkate, please don't spray to "kill any baddies" in the soil. You will kill goodies too.
Dried manure is fine but try and mix it with your soil. When you dig up your lawn for your new beds trench the,grass turves into the soil face/grass down....at least 6 to 9 inches deep.
I made a new bed from lawn last year., when I do this I try to move some mature plants from elsewhere in the garden into the new area....it adds immediate impact, maturity and scale. For example, a large yellow leaved dogwood, a couple of hellebores, a large grass or two, etc etc.
You should keep seedlings away from the manure though....it's too strong. What "seedlings" did you mean?

Probably no need to add much to soil in first year as there is lots of goodness there already...after all it has effectively been fallow for years appart from the grass which you are recycling anyway (nice and deep, and upside down or it will cause you heartache)

If you are a beginner I would only plant small plants which you can buy, or start the seeds in pots. Even the larger seeds can be reluctant to start, especially in cold soil.