Expose the plants during the day to a slightly cooler area, with more wind exposure. After about a week, the plants will have acclimated. Summer annuals and tender vegetables planted in cold weather won't grow well, and will often develop purplish leaf coloration. Plan to keep container plants for summer color watered regularly and fertilized every three weeks. The process of watering leaches nutrients away from the roots, so renewal fertilization is vital for summer color spots.
Many gardeners incorporate a timed-release fertilizer when planting.
This helps, because most potting soils in bags seldom contain plant nutrients. The bedding plants you buy, looking green and healthy, have received regular doses of fertilizer at the nursery while growing. They need it to sustain healthy growth. What you choose to fertilize with doesn't matter as much as using it regularly. Do not over fertilize with too much nitrogen, which will lead to leaves rather than flowers and fruit.