In the latest edition of the NC State Extension Gardner, Don Breedlove writes about straw-bale gardening
He says it saves space but requires more attention to watering and nutrients than traditional gardening. Vegetables that grow well in bales include lettuce, tomatoes, cucumbers, squash and eggplants.
Condition straw bales 10 days before planting. Place each bale at its growing location in full sun and on edge to keep the string from touching soil. Soak the entire bale for 3 days by slowly watering it. Over the next 5 days, add a high nitrogen fertilizer (such as 33-0-0) at 1 tablespoon per day and slowly wash it in. On day 9, add a complete fertilizer (17-17-17, 10-10-10 or 19-19-19) and water again.
Plant on day 10 and water again. One bale can hold 2 tomato plants, 6 cucumbers or 2 to 3 squash. A soaker hose will save time. Wilting indicates the need for watering.