So you took the leap and bought that houseplant you always wanted. In fact, that interior decorating shot you saw on a social media post, ‘inspired’ you to get a few. And why not? Plants make us happy! They increase the indoor oxygen and filter air too. You also made sure to buy only houseplants that are safe for babies and pets, since you share the house with others. This is good news and all very exciting. A life with plants can be a very rewarding one. As with many things in life we discover and learn new things on the way. This of course is true about houseplants too. One of the things you will discover is how important the condition of the soil is. However, the scope of this article only focuses on the importance of the pH of the soil and the houseplants that like acidic soil.
What is pH and why is it important for houseplants?
pH is the scale used to measure soil acidity. It runs from 0 to 10, with 7 representing the neutral point. Anything below 7 represents acidity and everything above 7 is alkaline. Houseplants that like acidic soil need a soil pH of about 6.5 and below.
If your plant is not looking too great, has yellowing of leaves, looks straggly, or hardly growing at all, you might suspect everything else, except the soil’s pH levels. The truth is that the right pH for your houseplants is crucial if you want them to stay healthy and flourish. This is because the right pH allows the plant to effectively absorb all the vital nutrients it needs to be happy. Nutrients vital for plant health include iron, manganese, phosphorous, copper, and zinc. Making any one of these nutrients available in large quantities to certain plants by raising or lowering the pH, may poison them. For example, when soil pH is too low for Geraniums, high levels of manganese made available becomes toxic to the plant. Conversely, the higher pH levels will set free toxic levels of molybdenum.
Houseplants that like acidic soil are also dependent on the creatures and organisms living in the soil. They are vital when it comes to healthy soil and plants and need slightly acidic conditions to thrive.
How to test the pH of houseplants that like acidic soil
Whether you have houseplants that like acidic soil living indoors or outside in the garden, testing the soil’s pH is easy. Try any of the following methods:
- Place 2 tablespoons of sample soil into a clean glass and add ½ a cup of vinegar to make it a little muddy. Observe how the vinegar reacts with the soil. If it fizzes or foams, your soil is alkaline.
- Place 2 tablespoons of sample soil into a clean glass and make it moist with distilled water. Then add ½ a cup of bicarbonate of soda. This time, if it fizzes or foams, you will know that the soil is acidic.
- You can also make use of pH strips. Place 2 tablespoons of sample soil into a clean glass. Add just enough distilled water so that it is the same level as the soil. Stir the soil and then let it rest for about half an hour. Filter through a paper coffee filter into a clean glass. Dip a pH strip and check the color to determine the pH. To get an average soil pH for your garden, repeat the same process but collecting soil samples from a few different areas around the garden.
How to adjust the soil pH for houseplants.
You can raise or lower the soil’s pH by simply adding one of 2 compounds.
To raise the pH, you can add limestone. There are two types of limestone, namely calcium carbonate and dolomitic limestone. Of these two, dolomitic is preferred as it also contains magnesium which is great for the soil and also neutralizes acidity better.
Houseplants that like acidic soil
Fortunately, most houseplants prefer soil to be on the acidic side. Find your favorite houseplants that like acidic soil from the list below as well as the corresponding pH levels for each plant. Also, find our top picks for maintaining your houseplants that like acidic soil further down below.
|African Violet||5.8 to 6.2|
|Amaryllis||6.0 to 6.8|
|Andromeda||5.0 to 6.5|
|Anthurium||5.0 to 5.5|
|Arrowhead Vine||5.5 to 6.5|
|Aster||5.8 to 6.75|
|Astilbe||6.0 to 8.0|
|Azalea||4.5 to 5.5|
|Basil||5.1 to 8.5|
|Begonias||5.5 to 6.2|
|Bird’s Nest Fern||5.0 to 5.5|
|Bleeding heart||6.0 to 6.5|
|Cactus||5.0 to 7.0|
|Caladium||5.5 to 6.5|
|Catnip||6.0 to 7.5|
|Camellia||6.0 to 6.5|
|Chinese Evergreen||5.5 to 6.0|
|Croton||4.5 to 6.5|
|Daffodils||6.0 to 7.0|
|English Ivy||5.5 to 6.5|
|Ferns||4.0 to 7.0|
|Gardenia||4.5 to 5.5|
|Heath||5.5 to 6.5|
|Hibiscus||5.5 to 7.5|
|Holly||4.5 to 5.5|
|Hydrangea||5.0 to 6.5|
|Iris||5.5 to 7.5|
|Japanese Pieris||5.0 to 6.0|
|Lily of the Valley||5.0 to 6.0|
|Southern Magnolia||5.0 to 6.5|
|Marigold||5.6 to 7.5|
|Monstera||5.5 to 7.0|
|Nasturtium||5.5 to 7.5|
|Peace Lily||5.0 to 6.5|
|Peperomia||5.0 to 6.0|
|Philodendron||5.0 to 6.0|
|Rhododendron||4.5 to 5.5|
|Rubber Plant||4.0 to 6.5|
|Snake Plant||4.5 to 8.5|
|Yucca||4.5 to 6.5|
Our favorite reads and TOP picks for maintaining your houseplants that like acidic soil
Miracle-Gro Houseplant Potting Mix
Specially formulated for indoor houseplants.
Fertilized, Perlite Soil for Indoor Gardening, Designed to Be Less Prone to Gnats, 4 qt.
General Hydroponics pH Control Kit for a Balanced Nutrient Solution
Makes pH testing easy.
For a Balanced Nutrient Solution.
Everything you need to maintain pH levels in the desired range, typically 5.5 to 6.5, in one handy kit.
SONKIR Soil pH Meter
3-in-1 Soil Moisture/ Light/ pH Tester Gardening Tool Kits for indoor houseplants that like acidic soil. Can be used outdoors too.
Soil meter tests pH value and sunlight level of houseplants.
Accurate, reliable, lightweight, and portable.
Plastic pH Test Strips
Universal Application (pH 0-14).
Laboratory and Diagnostic grade pH test strips for soil.
Contains 100 Strips.
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Little Book of House Plants and Other Greenery
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Wild at Home: How to style and care for beautiful plants
by Hilton Carter
Last thoughts on houseplants that like acidic soil
It is not hard to keep houseplants that like acidic soil healthy and happy, by monitoring the pH of the soil regularly. Since fertilizer can change the soil’s pH again over time, you may have to add either limestone or sulfur to keep things in the right shape.
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