Seedlings can generally go from indoors to a cold frame that is vented and lightly shaded for the first whole day outdoors. Increase exposure gradually by removing shading and covering until the young plants are tough enough to face the real world on their own. Some seeds may be directly sown in the garden. Fast-growing annuals, plants that are difficult to transplant, those especially subject to insect attack in the greenhouse and wildflowers are usually directly sown. All the organisms in garden soil cannot be controlled, but fortunately, sunlight and beneficial soil organisms limit seedling disease outdoors to a manageable level.
Bugs do prefer tender seedlings to tough adult plants.
This makes it especially important to wait until the weather is right and to see that the soil is fluffy and fertile so that seedlings grow rapidly past the most vulnerable stage. Outdoor-sown seeds will need the soil kept moist just as indoor seeds do. A daily sprinkle may be necessary. Be sure not to wash away or disarrange seeds with too hard a spray of water. In a rainy spring, it may be helpful to cover recently sown beds with old screens to prevent nature from dislodging them.