Answer: It is not too late to plant container grown grapes, but whether or not you would get a harvest would be questionable regardless. Bare root grapes should have been planted several months ago. The new plant will have to devote a lot of energy to rooting and becoming established rather than to fruiting the first year.
Here is some information about planting grapes you may find helpful.
Strawberries, watermelons and cantelopes all need a rich, organic, evenly moist yet well drained soil. You would remove any existing vegetation, then loosen the soil down about ten inches. Work in several inches of good quality compost or other organic matter, then level the area. You would need to run some basic soil tests to check the fertility and pH of the soil. Add fertilizer and/or lime as specifically indicated by the test results. After planting, plan on mulching your plants with an organic mulch to help keep down weeds and conserve soil moisture.
Here is some information about growing strawberries you may find helpful.
Here is information about melons. Some gardeners use black plastic over the soil rather than mulch when they grow melons. This is based on personal preference.
Your local county extension may have specific suggestions for growing each of these in your local area and soil conditions. Enjoy your garden this summer!
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