updating my mix - what should I add

originally put in 1/3 course vermiculite and 1/3 peat. Added 1/3 compost but probably did not use enough of a mix of 4-5. Each section of the garden is 4x3 and about 12 inches deep. Mix has settled about 2 plus inches in the past couple of years. Going to add 1 bag black kow composted manure, 1 bag each of Frey leaf compost and Frey mushroom compost and wiggle worm worm casting to each section. Couple of questions - how much worm castings per 4x3 section should I add and what additional compost would be good, assuming I can find it. I can order a 2 lb. package of Bat Guano which should be enough. What about seabird guano Good choices? Add 1 both or none. Anything else?
Best...... Steve

Be sparing with the rich worm casting. Think in handfuls instead of buckets for your small bed. The fact that you found mushroom compost, leaf mold and Black Kow manure compost, you did good. The recent thought is to limit manure composts to 20% of the total compost in order to prevent a buildup of phosphate. So, use mostly the mushroom and leaf mold with less than 1/3 Black Kow. All manures count the same so do not add bat guano or seabird guano. Look at the high phosphate level from fruit-feeding bats!!!

Insect Feeding Bats NPK

So on average, the npk value of bat guano is around N 10.0%:, P: 3.0%, K: 1.0%.

Fruit Feeding Bats NPK

So on average, the npk value of bat guano is around N 3.0%:, P: 10.0%, K: 1.0%.

Appreciate the response and makes total sense - thanks. So if I wanted to add one more item to the mix would any of the coast of Maine products work or is there something else you would suggest I seek out?

Best… Steve

The problem with Coast of Maine is that most of their products contain peat moss, plus other ingredients not needed or not wanted in Mel's Mix.  The labels often include the words "blend, mix, or soil."

If your beds were 7-8 years old and you have amended each year with more blended pure compost, then it wouldn't be so important.  In old compost, the peat moss has broken down quite a bit and refreshing with a small amount to get that tilth back is acceptable.  At the 7-8 year mark, my MM was getting heavy with lots of composts at various stages of further decomposing.  I added 1/2" of fluffed peat plus blended pure compost to the beds.  The following season I added 1/2" of coarse vermiculite.

If you wanted one more compost I would look for a veggie-based compost.

The quality of composts declined over the last 2 years and many people find they have to screen even the once-quality brands of wood and junk.  Part of the problem was/is a covid effect.  Folks started backyard gardening in droves and cleaned the shelves of seeds and everything gardening related.  Composters probably started bagging unfinished compost in order to meet the demand.

Photo from another site of a homemade sifter using 1/4" hardware cloth.  I recommend bringing the cloth up the sides and trimming with wood strips to prevent it from "biting".  Opps, can't find the photo so here is a photo of mine

Sanderson, struggling on this last one. Virtually every bag/manufacturer of veggie based I found is either out of stock, contains peat and/or manure. Would you have a suggestion of one or two that I could track down? 

Much appreciated.... Steve

Be careful of manures if you're going to plant root veggies.

Just pulled the turnips up today, and they're not round, but rather basically Red Bull cans with extra arms and legs.

Too much steer manure (nitrogen).  Also explains why they were attempting to do an imitation of ground cover, lol.

(they're still tasty, just odd-looking)

Steve,  The dearth of pure composts is real.  You did good finding 3 different sources (raw ingredients) plus worm castings.  Blend them and add as needed to bring the bed up to the original height.  Toss a few handfuls of castings and mix into the old Mel's Mix.

I know the book says 5 different composts but it is better to have 3 quality than 5 marginal.  Happy Gardening.

I realize how spoiled I am here in Maryland.  I don't have to search for multiple compost sources.  We have a company here that makes quality compost from a variety of organic matter.    The company is Veterans Compost.  I have been using it for many years.

Yes, Veteran's Compost has been a good compost.

They used to make up Mel's Mix for customers but they no longer use vermiculite, so we can't support that mix. They use rice hulls which do not have the same characteristics.

Now that the season is almost over I think I had a very good crop compared to prior years. I have 12 4x3 sections. This year, as mentioned, I added 1 bag black kow composted manure, 1 bag each of Frey leaf compost and Frey mushroom compost and wiggle worm worm casting to each section, both to raise the level of the garden a couple of inches but also for the nutrients.  Was not cheap but not sure I have to repeat. If I stay with the same mix, how much would each of the 12 sections need? 

Much appreciated...  Steve

so If I understand, I would take all three and mix them together then take 2 cu. ft. of that mix for each section?

Steve

Yes, blend the composts then mix in. My beds only have 7" of MM and it takes ~1" - 1.5" of new compost per year for growing year around.