When zinnia seedlings have two pairs of true leaves, they need to be thinned by pinching off all but the most vigorous seedling at ground level. Zinnia maintenance is very basic, just water, weed, and watch them bloom. Removing the weeds ensures that the zinnias are getting all the moisture and nutrients the soil has to offer, and it helps to keep the garden design attractive. Zinnias do not require a lot of water, but they should be irrigated during dry weather to keep them blooming at their best.
Trickle irrigation is best as sprinklers tend to increase the chances of disease.
Growing plants, such as zinnias, can help children learn how to garden and enjoy beautifying their outdoor environment. The success of a garden of zinnias in full bloom will be a source of pride and will encourage your young gardeners to tackle more projects in the future. Courtesy Virginia Tech., Horticultural Extension. Children enjoy many of the same pleasures as adults, whether it be baking, woodworking, or gardening. A main thing to remember, however, is that a child needs to start with a project that will provide both enjoyment and success to maintain a continued interest in the project.