"Our veggie garden was a bust. Everything grew huge, but we had no actual food except for the kale. Not much under the earth in carrots or radishes. Tomato stems are very big but not even one tomato is growing - the same for peas and cukes. Did we plant too much in one 8' x 8' planter?"
I wonder what fertilizer you used. It sounds as if your soil is overly rich in nitrogen. Nitrogen creates huge stems and leaves but does nothing to help fruiting. Perhaps you used a large quantity of manure or compost.
There's a problem if you grow crops that need different soil conditions in the same bed but fertilize the same way. Carrots and radishes like a little nutrition, but roots won't form if the soil is super rich.
Fertilizers have three numbers on the packet. The first is nitrogen, the second phosphorus and the third potash.
Phosphorus strengthens roots and helps plants produce fruit and seeds. Potassium (in the potash) also helps fruiting and increases disease-resistance.
Peas don't do well in high nitrogen situations. But you should have had some pods showing by now unless you planted them very late. Shady situations and pollination problems can also reduce pea crops.
Don't give up on your tomatoes or cukes just yet. It was a wet, cold spring and everything's late. Do you have flowers on your tomatoes?
It might be best to plant the bed in three squarish blocks: one for leafy plants, a second for root vegetables, and a third for anything that gives fruit (peas, tomatoes, cukes, etc.). This would also help with crop rotation.
Planting a bed of broccoli, head cabbage, lettuce or chard would help you use up all that nitrogen.
So would anything else where you eat the leaves, stems, or both.
"I would like to build up a landscape box, add more soil and make a hosta bed in the shade of my wisteria. Wisteria 'whips' grow all through the soil and I'm concerned these will leave no nutrients for the hostas.
"My plan is to place cardboard over the existing soil and build up the box and soil 'lasagne garden style.' I am removing the wisteria whips. Will this plan be okay for the hostas and the wisteria?"
Once wisterias begin suckering they continue every year - and the suckers will break through the cardboard before long.
You will have a yearly routine of cutting back the wisteria suckers.
Wisterias and hostas like moist rich soil so the two plants will be very good companions - and the wisteria suckers will keep coming no matter what perennials you use.
If you mulch yearly with compost or organic fertilizer, the hostas nutrient needs will be met.
The wisteria will get most of its nourishment much further afield.
Anne Marrison is happy to answer garden questions. Send them to her via firstname.lastname@example.org