Home-Made Soil Acidifier

The majority of plants can handle soil that is near a neutral pH, but some are really picky and they will let you know before long if you don’t give them the soil environment that they need.  Stunted growth and yellowing leaves are some of the more common signs that your soil pH is not where it should be.

What many plants naturally prefer is acidic soil.  This is due to two things: rain water is naturally a weak acid, and soil organisms create gases that acidify the soil.  Most plants originate in areas where these two things come together, and so it makes sense that this becomes a condition that they require for proper growth.

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Unfortunately, I don’t live in an area with naturally acidic soil.  On top of that, the irrigation water I have to use contains a lot of minerals (hard water), which counteract soil acidity.  This means my soil is on the slightly basic, or alkaline, side.  For the most part, my plants are okay with this and thrive, but I have a few that need a little extra attention.  In fact, I accidentally killed one blueberry, and nearly did in two others because I forgot about the pH of our sprinkler water.  I managed to save the two and they have grown tremendously in just a single season since I started regularly acidifying the soil again.

 How can you tell what type of pH your soil has?  Other than doing a soil pH test (which is actually pretty cheap and easy), you have a couple of other visual options.  If you or your neighbors can grow blue hydrangeas without any changes to the soil, lucky you, you have acidic soil!  Hydrangeas will grow pink flowers otherwise.  Also, if you live in an area that has volcanic soil, a lot of rain, and/or a lot of plant material on the ground (like decomposing leaves in a forest), you are going to have acidic soil.  Otherwise, neutral to alkaline it is.

 You don’t have to invest in expensive soil conditioners or do a lot of extra work to grow acid-loving plants.  You likely already have things at home that will work just as well.  The list below gives you multiple options to easily create the soil conditions needed by those acid loving plants.   The best part is that these options also reduce what you throw away and don’t generate any new waste!  Plants that will benefit from this are blueberries, gardenias, rhododendrons, maples, camellias, and hydrangeas.

 First off, when planting an acid needing plant, add a LOT of compost to the hole you are preparing to mimic the kinds of conditions that create acid soil in the first place.

• Brew a little extra coffee (1/2 cup) a few days a week and dilute with a couple of cups of water and pour onto the soil.
• Mix old coffee grounds with some water and pour around your plants.  You can also go to a certain famous coffee chain and ask for their old grounds.  They will usually be happy to part with them.
• Leftover tea and/or tea bags can be used just like the coffee.
• Got any lemon, orange, or other fruit juice that spoiled?  Dilute it down a bit and use.
• Pineapple peels?  Orange or other citrus peels?  Puree them to a pulp in a food processor, mix with water and pour around the base of your plant.  It will look messy and gross, but it will start breaking down very quickly and will be a major acid boost.  (If you don’t have a food processor, chop them as fine as possible and let it soak in water overnight before pouring onto your soil).
• Straining out your yogurt to make Greek yogurt? (recipe here!)  That liquid contains a lot of lactic acid that will do the job.  Again, dilute with water and use.
• Pile a lot of decomposing leaves around the base of your plant each fall.  This will allow the soil organisms to create an acidic environment just like in a deciduous forest.