Transplants go through a period of shock as they adjust to their new growing conditions. Bright sun, pounding rain and drying winds can all be a challenge for these tender plants. Their roots are limited to the container they were growing in but they need to reach far into the surrounding soil to seek out water and nutrients and to provide support to the plants as they become top-heavy. The important feeder roots grow horizontally through the soil where there is oxygen and lots of microbial activity, only a few roots grow down deep. To encourage that lateral growth keep the soil around the new plants moist and avoid letting it dry out. It should dry somewhat between waterings but for the first month, pamper these young plants with extra water during dry spells. By August they will be better able to withstand moderate droughts, but not now.
When planting seeds, bear in mind that before any leaves or shoots are visible above ground, roots have begun to grow. Keep the soil constantly moist a good inch deep until those first shoots appear. During this time you need to water more frequently but not so deeply. As the plants emerge and send out roots and shoots, water less frequently but more deeply. There is no hard rule here since it depends on the soil type and weather conditions. Sandy soil does not hold water and needs more frequent, brief watering. Heavy clay soil holds water too well and needs less frequent, but longer watering. Sunny conditions and especially windy conditions cause rapid water loss while overcast conditions can slow it down. When plants are pushing out lots of new growth they use more water.
Gardeners hate to hear this advice, but it really makes a difference. After planting marigolds, snapdragons, zinnias and other flowering plants, clip off the top flowers and flower buds. We have all seen marigolds with a big, single bloom on top, like an ice cream cone. That top bloom is inhibiting side shoots and blooms. By pinching it off, the side shoots will be free to grow and you will end up with a much bushier plant with many more blooms over a longer period of time than if you let that top flower stay. Those who are still unconvinced could try pinching some and leaving some of the same variety and then comparing the difference in a few weeks.
Weeds are the bane of any gardener; their number one pest. But keep at it! The first six weeks are crucial for plant establishment. Do all you can to stay ahead of the weeds now and you can slack off later in summer. Weeds are keen competitors for water, food and sunlight and can quickly weaken young seedlings and transplants. Do not wait for the weeds to become four inches tall before pulling. By that point they have already weakened your plants, and pulling them disturbs the developing root systems of your desirable plants. The earlier you can rub out weed seedlings the easier the job and the more effective the effort will be. Try to do a little weeding every day to stay ahead of them instead of one big weeding once a week. Just a few minutes before or after work can make a big difference.
Photo of young tomato transplants by Brian P. Whattam.