Cabbage grows well in the higher fertility levels found in clay soil. Cabbage is a hardy vegetable and is available in a variety of shades of green, purple or red. It should be transplanted early enough to be harvested before the heat of summer sets in. Using two or three varieties with different maturity times will give you an extended harvest. Cabbage thrives in moist ground and require consistently moist soil for good production. This is especially important during late spring and summer planting. Cabbage is ready for harvest as soon as the heads have formed.
Broccoli prefers to grow in full sun and in well-dug, heavy soil. The vegetable is very tolerant of frost and can overwinter in the ground. Soil moisture, abundant in clay soil, is especially important for broccoli when the heads are forming. Broccoli grows best in cool weather and does not do well in tropical, warm areas. If grown from seed, the vegetable is ready to harvest in eight to 10 weeks. Broccoli is rich in protein, vitamin C and fiber and is grown as an annual vegetable.
Brussels sprouts belongs to the cabbage family. The plant is slow growing and hardy in nature, able to overwinter in the soil under a heavy snow cover. Brussels sprouts plants thrive in cool and frosty weather and have a long growing time. The vegetable does not do well in regions with long summers. Ample soil moisture found in clay soils is essential for optimal growth, without which the crop is likely to fail. Harvest the vegetables when they are 1 inch in size and firm to the touch.