Spring-flowering bulbs and flowers you plant this fall burst into bloom next spring because food needed for flower development is contained in the bulbs at the time you plant them.
For flowers the second and succeeding springs, you must see to it at planting time that the soil for flowers contains nutrients which the plants can use to replenish the food used up the first spring. That is where garden soil preparation comes in.
NPK The Required Elements
Nitrogen, phosphorus and potassium are needed; organic matter in soil of these elements help create the best soil for flower beds because they become slowly available to the plants and remain in the soil for years.
Dehydrated manure, a good source of nitrogen. Use 10 pounds to 100 square feet. Bone meal, found at garden centers, supplies phosphorus and some nitrogen as well. Use about 5 pounds to 100 square feet. Potassium is had from wood ashes, and an application of 15 pounds to 100 square feet is generally sufficient.
Nutrients at the Roots
Because roots develop at the base of most bulbs, you must be sure that these materials are down in the root zone. Dig and mix them in the soil deeply.
Video How to: Prepare and Improving Clay Soil for Gardening
Improving Soil Quality And Structure
To improve soil structure and its ability to hold these nutrients, decayed compost and/or peat moss should also be worked into the soil prior to bulb planting. Spread a 3-inch layer over the planting area and mix it in to a depth of at least one foot.
The manure, the bone meal and the wood ashes may be worked in at the same time with other organic soil amendments. From 5 to 10 pounds of garden lime to 100 square feet may also be incorporated in the soil to sweeten it and improve its structure.
For either a drift of twelve or a bed of 100 bulbs, a good soil preparation is essential.
Soil Drainage Essential
But no matter how well you prepare the soil, if it is not well drained – if it remains wet for days after a rain and is soggy in early spring and late fall—the bulbs may simply rot away.
So, besides providing soil nutrients, choose a naturally well-drained location for your bulbs and flowers. The old advice about placing a cupful of sand beneath each bulb is absolutely ineffective in remedying the results of a poorly-drained soil.
Finally, foliage is necessary for the manufacture of food for bulk storage, so allow it to remain until it yellows.
If the spring season is very dry, it is advisable to water bulb plantings and flower beds thoroughly at least once a week to help the plants retain their foliage.
The more vigorous the foliage and the longer it lasts, the more food is produced and stored in the bulb. A commercial fertilizer, such as 5-10-5, sprinkled lightly among the plants and scratched and watered into the soil, is a further inducement for the plants to grow vigorously.