adding some small bark fines and or perlite will help. the amount of peat you added will determine how much you should add.

Protecting them from getting too much rain is all I can suggest if you don't want to remove the plants/seeds already planted. Otherwise I would add bark and/or perlite and/or pumice to the mix.

Are they really containers or just frames? If there isn't a bottom, then you just created yourself a raised bed and not a container. Just verifying.

The best remedy that I can suggest is - compost, compost, compost. Purchased soil is OK, but with the sphagnum moss in it, it takes a long time to absorb moisture, and must be kept evenly moist. I usually reserve it for mixing with my compost - using it to start seedlings under lights indoors.

For growing outside, I prefer my homemade compost.

You could try soaking your already planted areas, to try to work moisture in them, and not letting the moss dry out, as it will "wick" away moisture from the plants later.

Just my 2 c's. P.S. worm bins work well to make good garden soil too.

Bejay

Thanks for all of your responses!
The containers have bottoms with lots of holes drilled in the bottom and the whole thing raised off the ground by bricks.
My compost bin is new and the compost is not ready yet. I'm wondering if I am not testing the Ph of the soil and providing appropriate remediation or if I'm using all the same kind of soil i.e. nothing is 'sandier,' or 'richer,' than the other, will my veggies still grow? The more I read, the more I realize what I neglected to do and its overwhelming me. How precise do I need to be? Its my first time. THANK YOU!

Here is a link that might be useful: Photos of the progress

Add a lot of perlite and if available compost. The perlite will open up the soil to allow better drainage and allow the roots to get good air. The compost will help with nutrients and soil structure as well. It's never too late!