General Considerations:

If you don't want to put as much work into figuring out the exact pH of your existing soils then the following may be a good base line to decide if you need to take actions. Arid (dry) climates typically contain higher pH soils (basic) while wet and rainy climates have lower pH soils (acidic). This generally occurs because the wet climates have more rain and moisture that leaches the lime, or calcium, out of the soil. So consider the types of vegetables or other plants you want to grow, look at the ideal pH range for those plants (there is a table farther down this page), and decide if the climate you are in will require some soil adjustment measures or not. Of course you can always just choose plants that prefer the soil that aligns with the climate you are in as well.

 

The first step to creating a thriving garden is to understand the existing soil you are working with. The best way to get a general idea of your soil is to break it down into 3 components: clay, silt, and sand.

​

A easy way to break down your soil into these three components is simply using mason jars, some samples of your soil, and water.

​

Testing your Soil with the Simple Jar Test:

• Dig up soil samples from the areas you plan to plant in (take sample from about a foot  depth)

• Place soil samples from different areas in your yard in different jars (fill 1/2 each jar with soil)

• Fill the remainder of each jar with clean water and screw lids on tightly

• Shake each jar until all soil is suspended in water

• Place the jars on a flat surface and wait 24 hours

• After 24 hours the soil will have settled into different layers that look like this from top to bottom:

​

Organics

clay

silt

sand

​

• Measure the total height of the soil in each jar and record it

• Then measure the height of each layer and record it

• Now divide the height of each layer by the total height to get the percentage of your soil that is each soil type:                                

                                                      *100

​

• Remember that a good soil for general gardening is 40% sand, 40% silt, and 20% clay. Too much clay and your soil won't drain well, too much sand and your soil wont hold much moisture or nutrients.

​

The Importance of Soil pH

​

Soil pH is the #1 regulating characteristic for the amount of nutrients that your vegetation pulls out of the soil. Basically the closer that a soil pH is to the ideal pH for whatever you are growing, the more nutrients that your plant will be able to absorb. So it is vital to know the soil pH range for different plants and take a little bit of time to adjust your soil to the necessary pH. Soil pH is something that should be checked every year as it can change quite a bit over the winter depending on your region and type of native soil. If you keep an eye on it and add soil amendments every year, it is relatively easy to maintain the soil pH your plants desire.

​

Raising the pH of your soil

​

Definitions

• Lime (noun) - a white caustic alkaline substance consisting of calcium oxide, which is obtained by heating limestone and which combines with water with the production of much heat; quicklime.

• Lime (verb) -  treat (soil or water) with lime to reduce acidity and improve fertility or oxygen levels.

​

If your soil has tested as being too acidic (low pH) then there are a few different ways to raise the pH to your desired level.

​

Crushed eggshells:

Adding crushed egg shells to planting areas has been an age old home remedy for acidic soils that cause vegetable gardens to struggle. Some people claim that this is a myth and that the method has very little impact on soils at all, but a study carried out by Iowa State University says otherwise. The study shows that crushed egg shells was an effective liming source that continued to raise the pH of the soil until approximately 18 months after its application. With results that were close to those of traditional agricultural lime, treating with eggshells seems to be a good (and cheap) option for home gardens.

 

To treat your soil, till in  ground/crushed eggshells at least as deep as you anticipate your plants' roots to grow. Aim to till in 0.5 to 1 pound of ground/crushed eggshells for every 10 square feet (sf) of garden area. The optimum time to do this is in the fall after you have harvested your fruits or veggies from the previous season.

​

Reference from Iowa State University: http://www.agronext.iastate.edu/soilfertility/info/eggshell-lime.pdf

​

Ground Calcitic Limestone (Calcium carbonate):

If you have a larger garden area and don't want to wait around while you save up eggshells, then buying bulk ground calcitic limestone (calcium carbonate) may be a good option. To treat your soil, till in the ground limestone at least as deep as you anticipate your plants' roots to grow. Aim to till in 0.5 to 0.8 pounds of ground limestone for every 10 square feet (5 to 8 pounds for every 100 sf). Again the optimum time to do this is in the fall after you have harvested your fruits or veggies from the previous season.

​

Manufactured garden lime:

There is always the option to buy manufactured lime and garden soil stabilizers. One should do their research before buying certain types of soil stabilizers though because some have severe disadvantages when applied in certain conditions and many are bad for the environment. If you choose this option follow the application instructions provided, but it is still recommended that you apply the treatment in the fall after you have harvested your crop from the previous season.

​

Professional testing:

If you want to get real precise in reaching a certain pH and soil stability then you can have professional testing done (by garden supply store, Local Cooperative, or nursery). They should provide you with a test report that outline deficiencies in your soil and recommend specific materials and quantities to use for treatment.

​

Lowering the pH of your soil

​

After testing your soils, if found to be too basic (pH too high), there is no need to panic because we have outlined the following methods to get that pH down to the level you desire. If you live in a area where soils naturally contain a lot of lime (calcium), it will be very difficult to lower you soil pH quickly as the lime in soil is constantly dissolving and raising the pH back up. If you want to grow a plant that requires acidic soils (such as blueberries) but live in an area with high lime concentrations then the best option may be to plant in containers or raised beds. When planting in a container or raised bed you can import soil with the correct pH level and maintain/adjust levels more easily over the years. With that being said here are some of the methods that we have found to be most effective in lowering a soil's pH.

​

Sphagnum peat:

This soil additive is decomposed moss that is high in organics and is great for backyard gardens and raised beds. There are several different brands of sphagnum peat that are easily obtainable. Cover your planting area with 1 to 2 inches of the peat and till (work) it into the top 12 inches of soil. Sphagnum peat often has a pH ranging from 3.5 to 4.

​

Sulfur (powder or pellets):

This is likely to be the cheapest option for most people with the most drastic results but it also takes the longest amount of time (slower pH change). This method can also be referred to as granular sulfur, elemental sulfur, or flowers of sulfur. Note that this option can take up to 9 months to see substantial changes so plan ahead and begin lowering your soil pH a year or so before you plant your acid-loving plants. You can apply more sulfur to an area where there are currently no plant, like a garden bed you are preparing for the next growing season, as opposed to an area that already has plants that you would like to keep. Applying too much sulfur to an area with existing plants can quickly kill them if you aren't careful. Follow the instructions that come with the sulfur you purchase, they normally have a table that tells you the amount of sulfur to add relative the the square footage of your planting area to reach different soil pH levels.

​

Organic Matter:

Adding organic materials to your soil will always decrease the pH over time as well as increase the overall nutrient content and stability of your soil. The most common and effective organic materials are compost and composted manure. If you really need to speed up the pH lowering process or have a rather basic soil to begin with, we recommend covering it with an acidic mulch. Some good examples of acidic and organic mulches are; pine needles, pine bark, peat moss mulch, and shredded oak leaves. This method of lower your soil's pH with compost covered by an acidic mulch is likely the safest for any surrounding plants that are already in place and the best option for the long term health of your planting beds. This method can also end up being the most cost effective if you want to put a little time into creating your own compost from food scraps and yard clippings and/or if you have free access to the mulch materials described earlier (already have and oak or pine tree near by).

 

 

Getting the right soil pH for your vegetables

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​

​