The article was powered by Yahoo Scout, which generates key points based on AI, which may not always match the content of the article. The article suggests that many gardeners make the same mistakes throughout the spring that are quietly costing them weeks of growth, hundreds of dollars in wasted plants and fertilizer, and potentially an entire season of blooms. The most costly spring gardening mistake is the tendency to prematurely prune Spring-Blooming shrubs before they flower. The author suggests that delaying the process of hardening off seedlings can cause them to become more difficult for young plants. Never feed your garden in early spring, and never skip delaying the hardening process.