Drainage - When an area is poorly drained, four techniques can be used
to improve it. They are:
Construct raised beds using railroad ties, construction timbers, stacked stone, brick or other suitable materials. In many instances, this is an effective system to use. It must, however, be incorporated into the overall garden plan.
Incorporating organic matter. In many instances, incorporating 50%, by volume, of organic matter such as shredded pine bark or compost will greatly improve the drainage of the soil. If, however, the bulbs are to be planted with herbaceous perennials, high levels of non-composted organic matter should not be used.
Modified mulching system. In recent years, a planting system using pine bark mulch has been developed for heavy, poorly drained soils. In this system, the site is rototilled 4 inches (10 cm) deep, the bulbs are spaced properly and they are subsequently covered with 5 to 8 inches (12.5-20 cm) of 1/2 inch (1.25 cm) screened pine bark mulch amended with lime at the rate of five pounds/cubic yard. The mulch provides winter protection. This system also takes into consideration that most flower bulbs produce contractile roots. These roots will position the bulbs at the optimal depth for subsequent growth and development.
Installing drainage tiles. This is expensive, but it may be necessary if other alternatives are not available or useful.
Adjusting the soil pH - The optimal pH range for most flower bulbs
is 6 to 7. Therefore, the soil should be tested. If the pH must be adjusted,
the following information can be used as guidelines (Reference: Sudbury).
The amount of additive required to change pH depends on the type of soil. There are three basic soil types:
- Sandy soils - 60% sand, 15% clay and 25% silt. Water is absorbed quickly and they dry out rapidly.
- Loam soils - Equal parts sand, clay, and silt. Easily tilled and retains moisture. The best soils.
- Silt or clay loam soils - 25% sand and 75% clay/silt. Tends to compact. Water is not absorbed, but puddles and runs off.
The following additives can be used, to raise the pH 1 unit:
Pounds/1,000 Sq. Feet
Ground or dolomite limestone 68
Hydrated or spray lime 50
Marl or wood ashes 68
Oyster shells 68
Burnt lime 38
The following additives can be used, to lower the pH 1 unit:
Pounds/1,000 Sq. Feet Aluminum sulphate 15 Compost 150-200 Manure 50 Sludge 50 Green manure crop 10-12 oz of seed Flowers of Sulfur 15 NOTE: For sandy soils use 33% less. For silt or clay loam soils use 15% more.
All additives used to raise pH should be incorporated into the soil at least one week before fertilizer is applied. Hydrated or spray lime reacts almost immediately. Other additives take months and, therefore, should be applied in the fall of the year for the next growing season. Never apply more than 50 pounds of lime per 1,000 square feet per application and never mix fertilizer with lime.
Preplant Weed Control - Glyphosate (Roundup™) can be used to establish a weed free site before bulbs are planted (Reference: Skroch and Derr, 1992). Total site preparation time is approximately four to six weeks.
In order to plant flower bulbs in September to November, site preparation must begin in summer (August). Total preparation time is approximately four to six weeks using the following method: