Topping brand new SFG box with more gorgeous compost???

Hi!

I've been gardening (sort of haphazardly, just doing what I knew worked given my previously busy work and travel schedule) for 20 years, and am very excited to start SFG and to learn more.

I just filled a new raised bed with Mel's Mix. However, I only had access to 2 different kinds of compost, as my own was not ready. I purchased 'mushroom compost' and worm castings. I only had time to plant one square when I unexpectedly had to go to my sister's sheep farm in upstate NY.

And I came home with bags and bags of beautifully aged and composed sheep manure (probably about 500 pounds worth!). 

My grid is already in place on the bed, and that one square is already planted with carrot seeds, so would it be acceptable just to stir in some of the composted manure into the top several inches? Maybe to raise the soil level up about 2 more inches? It's just beautiful stuff and I'd really like to add it in without re-doing the bed or the entire Mel's Mix ratio.

Thanks so much for any wisdom and advice you care to share!

Jemm in western PA

The problem here, Jemm, is that you do not want a high level of manure or worm castings in the mixture.  Manure has a high concentration of soluble phosphorus, which throws off plants ability to obtain other nutrients they need. For example, too much phosphorus can induce micronutrient deficiencies of zinc and iron. Zinc deficiencies usually show up in early spring as a dwarfing and yellow striping between the veins of younger leaves. Nutrient deficiencies such as these are difficult to correct because they are caused by an imbalance, not a simple deficiency.

You already have a very high percentage of manures with the worm castings and mushroom compost.  Adding sheep manure will only make this imbalance worse.  I would suggest further composting the sheep manure with more plant material to have it for future use in the beds. Meanwhile, see if you can find some non-manure based composts to add to your bed.

Thanks, OhioGardener, that makes sense. And this is true even if this sheep manure has been composted for several years? It is mostly all dark and crumbly, no smell.

jemm wrote: And this is true even if this sheep manure has been composted for several years?

Yes, until it is composted with a large percentage of plant material it remains as composted manure. High in phosphorous.

Jenn, What OG wrote. The SFG Foundation recommends that manure-based composts be limited to 20% of the total blended compost. Worm castings, the honorary "compost", should also be limited to 5%. I have posted a decent article on phosphate buildup.

The only caveat was written by a Master Gardener of the "advisory and think group" of the Foundation. "I agree with a lot of what is written. The part I disagree with is when he talks about compost being high in soluble salts and that making your soil toxic. Pretty much every nutrient is in the form of a soluble salt before the plant takes it up dissolved in water. When people hear the term “salt” they think of sodium chloride that isn’t the salt that these organic compounds form."

Grab a cup of coffee for a good read.

https://www.facebook.com/texastestedseeds/posts/pfbid02McBiVt5YYb8dALYASjgE7NJCwHQHowKACWDjkXLPEhryazMawmbh6Z861uAh4Ly2l