The Tennessee Preppers Network has a fantastic post regarding fall planting if your up to the task, so go ahead over and read up to get some ideas and specific types of veggies to grow. Keep in mind the first frost date of your area, below are average dates for NJ Cities:
As for this post, I'll limit myself to Winter Cover Crops because that is what I will be starting on this weekend. First some definitions.
Winter Cover Crop
A winter cover crop is planted in late summer or fall to provide soil cover during the winter. Often a legume is chosen for the added benefit of nitrogen fixation. In northern states, the plant selected needs to possess enough cold tolerance to survive hard winters. Hairy vetch and rye are among the few selections that meet this need.
Summer Green Manure Crop
A summer green manure occupies the land for a portion of the summer growing season. These warm-season cover crops can be used to fill a niche in crop rotations, to improve the conditions of poor soils, or to prepare land for a perennial crop. Legumes such as cowpeas, soybeans, annual sweetclover, sesbania, guar, crotalaria, or velvet beans may be grown as summer green manure crops to add nitrogen along with organic matter. Non-legumes such as sorghum-sudangrass, millet, forage sorghum, or buckwheat are grown to provide biomass, smother weeds, and improve soil tilth.
A catch crop is a cover crop established after harvesting the main crop and is used primarily to reduce nutrient leaching from the soil profile. For example, planting cereal rye following corn harvest helps to scavenge residual nitrogen, thus reducing the possibility of groundwater contamination. In this instance, the rye catch crop also functions as a winter cover crop. Short-term cover crops that fill a niche within a crop rotation are also commonly known as catch crops.
For my use this winter I will be planting first the new crop of Garlic, that will go in the ground mid-September. I have the peas in the ground already as I actually remembered to purchase extra seeds this past spring. But the rest of the garden will get tilled, limed and split between clover and Buckwheat. I alternate which end gets planted with which just to keep in line with rotations.
A cover crop can be seeded as soon as the vegetable crop has reached maturity and has been harvested. In fact, cover crops should be sown while the weather is still warm enough for the seeds to germinate. After that time the seed is apt to just sit dormant and not germinate until the next spring, at a time when you really don't want these cover crops growing in your garden.
There's no special soil preparation for seeding a cover crop. Simply, spade or till the soil after harvest, and sow the cover crop seed. If you have late crops in a part of the garden, then simply sow the cover crop in the space between the rows.
Source: 'Ed Hume, Ed Hume Seeds, Inc. - www.humeseeds.com
So this weekend, I will be planting clover in one half of the garden and buckwheat in the other as well as adding some green compost to the soil. Pay attention to the crops you till in this year since the Tomato blight and other fungus or pest issues that may have arisien over the summer can stay dormant in your soil and show up again next year. Better to just pull the old stuff out and burn it than to have a continuous problem. If you have farm animals, or the stuff they leave behind, winter is a great time to get that mixed in as well. My grandfather was always good about spreading Manure in the fall and I'd swear his garden never had any problem producing more food than the family needed.