
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 screened pine bark mulch amended with lime at the rate of 5 lb/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.
Add additional mulch as necessary to protect the bulbs.
- 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:
|
Additive
|
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:
|
Additive
|
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 lbs.
of lime per 1,000 sq. ft. 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). 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:
- Be sure the area has not been mowed, so grass and weeds will be the proper
size at the time of spraying as specified on the glyphosate label.
- Spray only when the plants are dry. When the site meets these conditions,
uniformly spray the area for coverage but do not wet the plants to runoff.
- Allow at least six hours of drying time for maximum plant kill with glyphosate.
The timing of this first application should coincide with active weed growth
because the optimum susceptibility to glyphosate for perennial weeds is when
they are actively growing. In addition, they are most susceptible when they
are not stressed.
- Seven to ten days after the initial spray when the grass and weeds are
dying, till the site and prepare it for planting. This should be accomplished
by mid-September for planting in early October.
- If weeds emerge, retreat with glyphosate two to four weeks after the final
tilling and bed preparation. Tilling will bring new weed seed to the surface.
The soil will be warm and if sufficient moisture is present, many annual weed
seed may germinate. These seedlings will die within seven days after treatment
and the site will be ready for planting.
Consumer
Horticulture | Bulletin
41: Narcissus