Hooper`s Garden Center - Sulphur Application
Sulfur is indispensable for plant and animal growth. It is an essential ingredient in many amino
acids and is an important constituent of proteins and certain vitamins. Sulfur is necessary for
nodule formation on legume roots, and for seed production in all plants.
The importance of Sulfur in Gardening is directly related to pH. The pH value of soil and water is
a critical variable for all gardeners to consider. Particular crops and plants require a specific
pH to thrive and produce high yields. Whether it is growing tomatoes in a small garden or corn over
many hundreds of acres, knowing and maintaining the correct soil pH is a definite must. A pH of 6.5
is found to be the most favorable for the availability of all plant nutrients and is the pH to which
most soils and soil based composts are adjusted.
Nitrifying bacteria work best above a soil pH of 6.0; consequently, nitrogen is more available for
plants to use. Vegetables vary to some extent in their requirements, but most garden crops will do
well with a soil pH of 6.0 to 6.5. This is a little below neutral, or slightly acidic. If soil pH
is too high or low, poor crop growth will result, largely due to the effects pH has on the
availability of nutrients to plants.
It may not be possible to water with pH adjusted water, but it is still helpful to test the
water source to know which way it is moving the pH of the soil. For container plants that are
watered by hand it is possible to easily correct the pH of the water using vinegar or the same
pH-down products used in hydroponics.
Disintegrating granulated Sulfur is an acid producing mineral used to help lower the pH
of alkaline soils and provide essential Sulfur to garden plants. For general garden use and
for use when planting new lawns, sulfur is best applied one to two weeks before planting and
fertilizing. Ideally before applying sulfur determine the soil pH using a test kit that can
be purchased for around $5.00. Water pH test kits can be purchased for less than $6.00 while
meters that are inserted into moist soil to test pH can be purchased for $8.00 and up. Most
of these kits come with charts showing the optimum pH for various garden plants and if they don’t
come with the kit, such charts are available here at Hooper’s.
Please follow the recommendations below to determine the proper amount of Sulfur required:
Amount of Sulfur Required to Lower a given pH to 6.5 for different Soil Types
| Existing pH | Sandy Soil | Clay Soil |
|---|
| 8.5 | 3.5-4.5 lbs/100 sq. feet | 4.5-6.0 lbs/100 sq. feet |
| 8.0 | 2.5-3.5 lbs/100 sq. feet | 3.5-5.0 lbs/100 sq. feet |
| 7.5 | 1.0-1.5 lbs/100 sq. feet | 2.0-2.5 lbs/100 sq. feet |
Caution: For regular upkeep of soil pH on an established lawn no more than 0.5 lbs/100 sq. feet
should be applied at one time. If more Sulfur is required, applications should be made a few
months apart.
After Sulfur application mix well into soil or lightly work into soil surface of established
plants making sure not to damage surface roots. Water thoroughly after feeding application.
Certain plants require a more acidic soil for proper growth. These plants include:
| Peppers (5.5-6.2) |
Potatoes (5.5-6.0) |
Tomatoes (5.5-6.3) |
Blueberries (4.5-5.5) |
Courtesy of Hooper`s Garden Center
2205 Mt Highway 35 East
Kalispell, Mt 59901
(406) 752-2770
www.hoopersgardencenter.com