Soil Testing: How to test your garden soil

Want to have a better, more productive garden this season? It all starts with a healthier soil. Soil health is one of the key factors in the success of your garden. Now’s the time, before you start planting, to understand your soil, by testing three important elements: structure, pH, and nutrient content. You can test your garden soil yourself and get reliable results. Here’s what you need:  

A home soil testing kit, such as a rapitest soil test kit.  

An empty Mason Jar or peanut butter jar.  

A scoop for gathering soil.  

Garden gloves.  

Rapitest offers a 10-test soil pH test kit as well as a 40-test kit that will allow you to check Nitrogen (N), Phosphorus (P) and Potassium (K) in addition to pH.   

  

  

All you do is take a sample of soil, mix with water, transfer some of the solution to the color comparator, add powder from capsule, shake and watch the color develop. Then, note your test results. Fast, easy and it only takes a few minutes.   

Soil pH is a measure of the acidity or alkalinity of a soil. On the pH scale, 7.0 is neutral, above 7 is alkaline, below 7 is acidic. Bleach for example is very alkaline. Lemon juice is very acidic. Most plants prefer a pH of between 6.5 and 7. Our soil is typically greater than 7.   

 

Adjusting soil pH can best be accomplished by incorporating organic material to your garden or raised bed. Organic soil amendments are preferred because they help balance the soil structure as well as pH naturally.   

Utilizing soil sulfur such as Hi-Yield soil sulfur does work, but it’s a very slow process totally dependent upon the microbial population of your soil. The transformation of elemental sulfur in your soil involves both chemical and biological processes, but its primary driver is biological.    

In addition to pH and nutrient levels, the structure, physical makeup, and organic content of your soil has a direct impact on your garden’s productivity. Whether you’re growing in a raised bed or an in-ground one, the quality of the soil affects everything from strong root development to flower and fruit production.  

The Jar Test is a quick, easy way to help you determine the structure and physical makeup of your soil. You’ll need a clean jar with a lid, in this case a peanut butter container. Put 4-5 ounces of soil in the bottom of the jar. Add enough water to fill the jar 2/3 full.  Add a drop or two of dishwasher soap. Put the lid on and shake well, then let the jar sit undisturbed for 24 hours. You’ll see that the soil has settled into layers.   

The first layer will be sand. The second layer will be silt, followed by clay, suspended clay, then a small amount of organic material, floating at the top. This is evident in the jar on the left. Typically, you’re going to see a small amount of sand and silt, a large percentage of clay and a small amount of organic material. 

 

As you add more organic material to your garden, your test results will look more like the jar in the middle. The jar on the right illustrates a well-amended garden soil: dark and rich, with more organic material suspended in with the clay.   

As a rule, to improve your garden soil and lower the pH, you need to add more organic material in the form of sheep manure and organic compost. We recommend you add two to three inches of locally produced organic material to your garden in the spring and again in the fall.  Coconut coir and worm casting are also good choices for improving your garden soil.  

If you’re looking for a more comprehensive evaluation of your soil, Colorado State University also offers soil testing. Follow this link to learn how take and submit a sample for analysis:  https://agsci.colostate.edu/soiltestinglab/ 

 

Whether you test your own soil or use CSU’s lab, bring us the results. We'll recommend the right amendments and fertilizers to make your garden soil healthier and more productive.   

 

How To Keep Your Flowering Bushes Healthy and Blooming

 

Seasonal pruning is an excellent way to help keep shrubs beautiful and healthy! Pruning ornamental shrubs and vines is the way to improve plant health and vigor, control size and shape, to increase flower production, as well as remove overcrowded, damaged stems and branches. Pruning should be part of the regular maintenance and upkeep of your garden, whether your shrubs bloom in spring or summer.    

Along with learning how to prune, gardeners should know the best time to prune the flowering shrubs in your landscape.  Knowing when to prune flowering shrubs is especially important because if you prune your shrubs at the wrong time of year, you may inadvertently remove the flower buds for that season.  

March is the right time to prune many of the shrubs and climbers in your landscape. Pruning these flowering shrubs and vines isn’t difficult if you understand that getting the most from your flowering shrubs depends on three things: using the right pruning tools, knowing when to prune and knowing how to prune.  

For pruning shrubs, it's important to have the right tools to make clean cuts and promote healthy growth. This includes hand pruners, loppers which providing extra leverage for cutting thicker branches, and gloves. 

When it comes to knowing when to prune, flowering shrubs can be divided into two types: spring blooming and summer blooming. Spring blooming shrubs such as forsythia, lilac, ninebark and weigela already have this spring's flower buds in place.

 

 

They're said to bloom on "old wood" because soon after flowering last season, these types of shrubs begin to set the buds for this season's blooms. If you prune these shrubs now, you'll remove most of the flower buds. The time to prune ornamental shrubs that flower in spring and early summer, is within a month after they stop blooming. 

Summer flowering shrubs such as butterfly bush, blue mist spirea, potentilla and hardy hibiscus can be pruned now, because they bloom on this year's growth or "new wood".  

 

Summer flowering hardy hibiscus (Rose mallow) and butterfly bushes (Buddleia) do best if you cut them hard to the ground now. You can use a lopper to cut the canes.  Don't worry! They'll grow back and bloom vigorously.  

 

For Blue Mist Spirea (Caryopteris) prune the stems back to about 4” to 6” from the ground. This may seem drastic, but this will encourage a better bloom.  

For Potentilla, remove up to about one-third of the plant’s growth, thin out the center for better air circulation, and clean up any dead or diseased wood. 

 

Many gardeners prefer to prune Rose of Sharon (Hibiscus syriacus) after it has finished blooming in the summer. This is because Rose of Sharon often produces blooms on the current season’s growth (or, depending on the variety, on last year’s wood). Pruning soon after flowering helps avoid removing potential flower buds. 

 

If you’re uncertain about the blooming habits of any of the shrubs and vines in your landscape, it’s best to not prune until you’ve had time to observe each plant’s growth and bloom cycle. Then you can decide the right time to prune.   

The exception would be any broken, dead or diseased branches.  These conditions call for pruning as soon as they occur.  

This is also the time to prune Group 3 Clematis. These varieties bloom on new wood in late June into August. They should be cut back to a living bud at about 24" from the ground in spring just as the buds begin to swell. If you don't prune, the flowers will tend to be only up at the top of the plant and the bare stems will be unattractive below. When to prune Clematis can be tricky depending on the bloom time and variety. If you’re not sure, don’t prune.  

After you're done pruning, give your ornamental shrubs a good drink.

Wait another month to start feeding your shrubs. When you do, select a fertilizer such as ferti•lome Gardener’s Special 11-15-11.  

Pruning shrubs can be somewhat intimidating. If you have questions about pruning in general or how to prune a particular shrub, stop by our Diagnostic Center.  We'll help you figure out what to do. Learning how and when to prune will keep your shrubs healthy and blooming for many seasons.