Q.Potting Soil
We have nothing but sand in our yard, so I have dug a hole 4 feet by 12 feet and 18 inches deep, filled with potting soil. I mixed steer manure just under the seeds, but they are not doing well (cucumbers, beets, lettuce, beans and zucchini). A few cukes and zucchini have come up, but I see no signs of the lettuce or beets. Should I have mixed sand with the potting soil, or what can I do at this point?

Certified GKH Gardening Expert
These articles should be helpful: https://www.gardeningknowhow.com/garden-how-to/seeds/using-potting-soil-in-the-ground-to-start-seeds.htm
https://www.gardeningknowhow.com/special/organic/the-importance-of-soil-for-an-organic-garden.htm
https://www.gardeningknowhow.com/garden-how-to/soil-fertilizers/what-is-soil-made-of-creating-a-good-garden-planting-soil-type.htm