Hello from a new gardner in central Wyoming

Hi, I'm 61 and just rented a house with two 4x8 raised gardens already in place, but I don't think used for manyt years. The soil looks like it may have been pretty good. There is about 4" of space between the soil and the top of the sides. I've never done a raised garden before. I found a book I bought in 1989 on square foot gardening, so I bought the newest version and am intrigued. I have purchased the vermiculite, compost, and peat moss, then realized I didn't buy enough. Then I bought a wheel barrow. Now I need to go get a tarp to mix the soil. There is some shade covering them, but I'm hoping enough sun for pole beans, corn, tomatoes, bell peppers, red onions, sweet potatoes, watermelons, jalapeno, peas, and cilantro (can you tell I want to make my own salsa?). I'm going to try planting beans and corn from seed. Any advice would be good. We're at about 5500 feet.

Welcome!

I didn't use a tarp.  It's just me and I have enough problems with my back.  I found it easier to use a hoe and my wheelbarrow. 

For my 4'x8' bed I built 6/1, I measured the peat moss and vermiculite with 5-gallon bucket of each into my wheel barrow then mixed with a hoe.  I did NOT dampen it because it was already slightly moist since I had fluffed my peat moss the week before and stored in an open trashcan under the porch.  The south is HUMID all year round, but especially spring/summer. 

I poured this out into the bed and made more until the bed was 2/3rds filled -- at the time I kept track of the number of wheelbarrows, but can't remember now how many that was. 

Then I started blending composts in the wheelbarrow, a half a 5-gallon bucket of 5 kinds, then stirred with my hoe by raking it to the back of the wheelbarrow, then moving to the other side and starting at the bottom of the pile, and raking it to the front of the wheelbarrow, etc. until it was mixed well.  Since the composts were different colors, it was easy to tell when it was NOT mixed well.  Kept going until it was.  Then I dumped in the bed. Made more until the bed was nearly filled. 

Then I used the hoe in the bed the same way -- raked it all to one side, went to the other side and raked it back pulling from the bottom of the pile.  Since the peat and vermiculite LOOKED different than the compost blend, it was easy to tell when it was all blended together.   Without added water, it was also LIGHT WEIGHT so I didn't do this on a windy day.

Then I let the rain wet the bed and CHECKED to make sure the bed was soaked all the way through with a moisture meter.  It was.   But it was a good hard rain for 2 hours, so that helped.

Make sure you measure -- many people use a 5-gallon bucket. 

Since you've got existing "soil" in your raised bed, I'd want to use something like a garden fork and double dig that -- mix it up good by prying the soil up with the fork.  That way you can remove anything you don't want -- weeds, rocks, trash, etc.  And you loosen it so roots can get down into it once they leave your Mel's Mix.  You've only got 4" of space, and Mel's Mix settles A LOT, so you might want to think about removing soil so you have a good 7" of space and fill it FULL for later settling.

What 5 composts did you find?  I used mushroom compost, Black Kow, Black Hen, Nutri-fibre with bio-char, and aged horse stall leavings. 

Make sure you FLUFF your peat moss if it's in a compressed bale.  I did this by just rubbing chunks of it between my gloved hands until it disintegrates -- one of the few things I do with gloves, but this is course stuff.  And the 6/1 bed I actually used cocount coir instead of peat.  As a test.  It's a LOT more expensive and I won't be doing that again unless I see a SPECTACULAR difference between that and the other beds.  The cost difference was $10 for peat or $30 for coir.

And make sure and enjoy yourself!