Test Your Potting Soil Quality Before Planting Your Container Garden

testing potting soil quality before planting


All potting soil blends are not created equal. The quality of your container gardening mix can fluctuate from bag to bag even among the best brands. To ensure that my container gardening soil is what I expect it to be, I like to test it before using the whole batch.

After a few years of container gardening you’ll become an expert at analyzing how good the mix is just by lifting the bag off of the ground. If the bag is heavy you’ll know that it may contain too much organic material. If the bag is too light, you know that there isn’t enough organic material. Through experience you know when you find that perfect bag of potting soil because it feels just right.

Here’s a simple test you can do at home before planting and finding out the hard way that your potting soil mix stays too wet or too dry for your plants.

Step 1.

Take some of your potting soil and fill a medium-sized pot with your soil straight out of the bag. Ideally this should be in the spot in your garden, porch, or balcony where your container garden will go.

Step 2.

Give the soil a good watering. Observe how quickly or slowly the excess water leaks out of the drainage hole. Leave the pot with the wet soil for a couple of days in the spot where you container garden will be planted.

Step 3.

After a couple of days come back to the container and examine the soil by digging around in it with your fingers.

Questions and Observations

Is the soil soggy after a couple of warm days? Has the soil dried out completely even though you had rain during your experiment? Take the container and turn the soil into the palm of your hand. Does it have the consistency of a mud pie? Is it dry and crumbling?

How to Amend Potting Soil

Soggy potting soil is not good for plant or root growth. You’ve probably experienced green algae growing on the surface of your containers from soil that has too much organic material and doesn’t drain properly. Potting soil that stays excessively moist can be amended by adding construction grade sand or vermiculite. Aim for a soil mix that looks “fluffy” when moist.

Soil that dries out too fast doesn’t retain moisture and is equally problematic. You want good drainage but enough moisture retention so the plants growing in it don’t have to be watered multiple times a day during the height of summer. You can amend dry potting soil by adding cocoa coir or compost. Again aim for that “fluffy” texture.

I once told a friend that my favorite potting soil looked good enough to eat. It sounds weird, but that’s what I aim for. It should look as delectable to you as it will be nourishing to the fruits and vegetables you'll be growing in it. Like a good chocolate cake, a properly balanced potting mix should be dark, rich, moist, and crumbly.