Nitrogen, phosphorous and potassium are the main macronutrients that your flowering plants need, along with water, fresh air and sunshine. There are also micronutrients they need in smaller amounts, including boron, copper, iron, zinc and chlorine. Fertilizing your flower beds the right way is important for getting healthy colourful blooms.
You should start fertilizing before you begin planting, in order to give your plants a good start. Don’t start too soon, though; it is best to add the fertiliser a day or two prior to planting. Start by spreading a high nitrogen granular fertiliser over the planting bed evenly, using the recommended amount from the manufacturer’s label, which will typically be 2 to 3 cups fertiliser per 100 square feet.
You should use a complete fertiliser mix which has nitrogen, phosphorous and potassium, unless the soil has been tested and been shown to contain sufficient phosphorous and potassium. Be sure to wear gloves if spreading by hand.
The next step is to balance the soil pH if required, by adding lime or sulfur. To make the soil more alkaline, lime has to be added to the flower bed soil. To make it more acidic, sulphur is added. Use a soil test kit if you are not sure what the pH is.
After you have adjusted the pH of the soil, it is time to add organic matter. Spread a 2 or 3 inch thick layer of finished organic compost or composted manure. You can make your own compost or buy it in bags at the garden center nearest you.
Now work everything into the soil thoroughly. Use a rototiller or a shovel to turn over the soil a few times. The goal is to get the nutrients of the fertilizer to where it will be available to the flowers’ roots. Beware, though, when transplanting, to not let the plants roots directly contact the fertiliser. High nitrogen content can burn a plant’s exposed roots. Instead, protect the roots by lining holes dug for transplants with regular soil, and use the same to fill the hole up.
After you have planted your flower garden, thoroughly water the plants.
Re-fertilize again every four to six weeks. In sandy soil, nutrients wash out quicker, so you may need to fertilize at shorter intervals if you have this type of soil. Both granular and liquid fertiliser can be used for this phase; remember to water after fertilising if using granular fertilizer. For best results, water before using either type of fertiliser as well; this prevents roots from being burned by the nitrogen content.