Some vegetables are best started from seed directly in the garden, while others are best planted as young plants (transplants). Fast-growing, cool season crops such as lettuce, radish and spinach are really best suited to direct seeding into the garden. Some that have really fine seed, or particularly long taproots such as carrots, do not transition well as transplants and perform best if seeded in place. Sweet corn and beans are also usually direct seeded to the garden.
Some crops can be successful with either direct seeding or transplanting, including cucumbers, squash, melons and pumpkins. While the same could be said of peppers, tomatoes and eggplant, gardeners will be able to harvest their crops much earlier by starting with transplants.
Good quality transplants require high light intensity, proper temperature, good-quality growing media and ample space. Some gardeners can provide those conditions well enough to start their own transplants at home. The advantage to growing your own is the vast array you can order as seed. But if you can’t supply adequate growing conditions, you’ll be disappointed with spindly plants that lack good vigor to make the transition to outdoors.
Most gardeners will purchase transplants from local garden centers. While many are tempted to select transplants that have already begun to flower or are already bearing cute, little fruits, knowledgeable gardeners opt for young, vigorously growing plants that are concentrating all their energy on growing leaves and roots. Look for stocky, stout stems and healthy green foliage. These vigorous juvenile specimens will make the best transition to outdoor conditions. Plants that lack sufficient roots and foliage cannot support much crop.
If you haven’t already, set out your cool-season crops such as broccoli, Brussels sprouts, cabbage and cauliflower when soils are dry enough to work. Warm-season crops such as tomatoes, peppers, squash, cucumbers, melons and pumpkins need warm soil, as well as frost-free air temperatures. This year has been quite slow to warm up, compared to average years. Laying clear or black plastic mulch on top of the soil 2-3 weeks prior to planting will facilitate soil warming. Black plastic will also provide weed control.
Predicting frost-free dates is certainly a game of chance, but if you look at the statistics for Indiana, you can divide the state into roughly three sectors. The average last spring frost (36 degrees F) in the northern half of Indiana falls between May 2-11. Most of southern Indiana falls between April 22-May 1. Extreme southwest Indiana falls between April 11-21. There are pockets of exceptions throughout the state and the microclimates in urban areas and up close to houses can permit earlier planting in many home gardens.