In my recent article in the Falls Church News-Press I write about creating an almost instant no dig garden bed by using berms. The berm consist of putting down a layer of manure (composted never fresh) first and then a 3-5 sheet layer of wet newspaper, compost, sand, shredded leaves, manure and more compost to make a berm about 2-3ft high. Water the layers well. Then plant directly into the berm. The materials in the berm will shrink as the organic material decomposes. You can leave the new beds as piles or better yet, make raised beds with frames of untreated lumber, bricks or cement blocks. Cement blocks are useful because they provide holes where you can plant herbs. If you have deer and rabbits or a digging dog you will need to fence the vegetable patch.
For small urban gardens and berms sow vegetable seeds in square foot sections instead of rows, thinning as they grow eventually keeping a few strong plants to flower and fruit. Maximize space by using a fence or poles to grow squash and cucumbers vertically instead of sprawling all over the garden. Also, there are bush varieties of peas, beans and squash that take up a bit less room. As for tomatoes, eggplant and peppers, it is too late to start them from seed, so just buy the plants from a garden center and plant them no earlier than the first week of May. Do try to keep vegetable beds to 4 foot square to make harvesting easier.
Succession planting means that the gardener plants early vegetables and then as the first ones are harvested plants the next season of vegetables in the same spot. In some cases the seeds can be sown together since some vegetables take much longer to reach maturity than others. Radishes and carrots are often planted together since the radish will mature much faster, breaking up the soil for the slower germinating carrots. Just as the carrot plants are starting to show their leaves the radish is ready to pick. Cooler weather plants such as beets or lettuce can be followed by warmer weather plants such as annual herbs like basil or tomatoes and peppers.
Interplanting is using one space for more than one plant. The Native Americans did this with what they called the three sisters: Corn, beans and squash. The beans used the cornstalks to climb, the corn was fertilized by the beans' nitrogen fixing roots and the squash crowded out the weeds and also used the extra nitrogen in the soil. You can also use a bush bean or trellised cucumber to shade lettuce or arugula for growing in the hotter months.