Pinch Seedlings of Annuals:
Keep an eye out on the progress of annual seedlings growing indoors. If they become too spindly, consider pinching back the growing tips to encourage branching and make them more compact.
Nearly all perennials like a boost just as their new growth starts to emerge. Topdress the soil with nutritious organic matter such as compost or add natural slow-release fertilizers. These foods will last longest and are less likely to burn tender plants.