My local community gardening organization gave me plans and instructions for constructing and filling a raised bed. They said to use half top soil and half compost, in layers. I foolishly did not follow the instructions, and instead used a local "garden mix" which supposedly had half top soil and half compost and also a bit of sand.
However, this mix does not drain well. After watering gently for only 2 or 3 minutes, puddles already start to form. I think that supplier made their mulch by breaking up old pallets and then composting them.
Except for the drainage problem I've been pretty happy with that mix I bought.
I propose to mix in some perlite or vermiculite or both, to improve the drainage. (In the spring I could put some compost on top as well.)
What factors should I consider when choosing between perlite and vermiculite? I like to grow lettuce, baby spinach, kohlrabi, sugar snap peas, ground cherry, tomatoes, zucchini and sticky corn.