acidifysoil

Organic & Natural Fertilizers,
Pesticides, & Herbicides

The secret to acidifying your soil for your acid-loving plants

Growing acid-loving plants in our area can be a challenge because the soils here tend to be more alkaline than some of the plants need. To complicate the matter, the tap water we use in our gardens tends to be alkaline due to the treatment methods used.

There are a few pockets of soil in our area that do have a well-balanced pH. You can often tell simply by digging into the ground. If the soil consists mostly of clay, it will likely need amended– but a more loose-looking, rich soil may be fine. If in doubt, you can have your soil tested at the Purdue Extension Office.

Beautiful newer Blue Hydrangeas like the ‘Endless Summer’ and some ‘Forever & Ever’ varieties will bloom a beautiful deep pink if the soil is not acidic enough. But if you want to keep the blossoms blue, you’ll need to do a little extra work. Remember– making your soil acidic does not change the color of any other Hydrangea varieties, or other plant flower colors.

Great new Blueberry varieties are now available for the northern climates, but they too must have a constant acidic soil to stay healthy and produce copious amounts of fruit.

Some of the other acid-loving plants should also have an additive at planting time, and often times need more added throughout their years of growth. You will get the best results by acidifying your soil at planting time.

To acidify your soil successfully for new plantings, we at Neuhouser’s recommend the following:

         1. When planting, mix 1/3 home-made compost, Peat Moss, or Mushroom Compost with your
              original soil which will add organic acid compounds to the soil. However, it may also hold more
              moisture than the plant can tolerate, so be sure to plant the item high (6-10” depending on the
              size of the shrub) and mound the soil gradually down.

2. Mix Aluminum Sulfate well into the soil surrounding the root ball. Use about 1 cup per 3’ of
plant. Don’t use too much– it may burn the plant.

         3. Finish planting per our Planting and Instruction Pamphlet, including using Root Stimulator after
              watering the plant very thoroughly. Use the Root Stimulator once a week for the next 2-3
              weeks, then once per month for the rest of the watering season. This will help get your plant
              established as the roots are able to absorb these nutrients quickly!

4. Finish by mulching with 2-4” of Hardwood Mulch (hardwood adds beneficial organic compounds
as it decays. Most other mulches may last longer, but do not enrich the soil.)

5. Fertilize every month through the end of July with an organic granular low nitrogen fertilizer
like a Vegetable or Flower fertilizer from Dr. Earth.

6. At the end of the season, add another 2 inches of Hardwood Mulch for extra winter protection,
especially for the first year.

For established plants:

Blue Hydrangeas

· We recommend an acid-loving fertilizer like Dr. Earth Azalea food in spring (April), followed by a low nitrogen fertilizer like Dr. Earth Rose & Flower twice a year (mid-May and late June) to keep them full of flowers.

· If the flowers are still not blue, water your plant well and dissolve two tablespoons of Aluminum Sulfate per gallon of water in a bucket. Water in the Aluminum Sulfate around the Hydrangea every two weeks until you get the blue color desired. Water the soil only– never the leaves or blossoms!

· Depending on your soil, you may even find it necessary to mix in a little more Aluminum Sulfate into the soil every couple of years. For more organic methods, see the “Tips” below.

For Happy Blueberries

· We recommend an acid-loving fertilizer like Dr. Earth Azalea Food in early spring (March) followed by a low-nitrogen fertilizer like Dr. Earth Vegetable food twice a year (late April and Late May) to keep the berries big and plentiful!

· If you see signs of yellowing on the tips of the leaves-or other signs of stress– after the first two years you may need to add a little more Aluminum Sulfate.

· Do note that in the first 2 years, yellowing can be assign of other things, particularly over (or under) watering– so be careful!

For Rhododendrons & Azaleas:

· The key is to get these well established first! So, the second year we recommend using 3 more applications of Root Stimulator one month apart.

· We also recommend holding off on the acid-loving fertilizers until the third year. Then use the Dr. Earth Rhododendron & Azalea food every year in spring– after they have finished blooming.

· Follow this with one application of Dr. Earth Rose & Flower fertilizer in June.

· If you see signs of yellowing on the tips of the leaves– or other signs of stress– after the first two years you may need to add a little bit of Aluminum Sulfate. Again yellowing leaves can be a sign of over or under watering, so be careful. These plants are easily drowned out, so be sure to plant high for good drainage.

For other healthy, acid-loving Evergreens & Plants:

· For Hollies, we recommend planting as described above. It would be wise the second year to use 3 more applications of Root Stimulator one month apart. All years thereafter, use an acid-loving fertilizer like Dr. Earth Azalea food.

· For all other Evergreens and other acid-loving plants listed, we recommend planting per our normal Planting & Care Instructions and using an All-Purpose fertilizer every May thereafter (Dr. Earth All Purpose is perfect!).

· On ALL of the plants, if you see yellowing of leaves or needles– or other unhealthy signs– check the moisture of the soil to be sure it is not too wet or dry. If the soil seems appropriate, you can add more Aluminum Sulfate (not too much). If you have questions– don’t hesitate to call us!

Other Tips:

· Planting near a sidewalk or foundation can make your work even more difficult, because the lime from the cement will continuously leech into the soil– making it more alkaline and less acidic.

· Over-using Aluminum Sulfate can be harmful to your plants. It is best when used at the time of planting or when quick action is needed only. Using it on a constant basis is not good for the soil.

· When possible, water plants using rainwater collected in rain barrels or well water rather than tap water which counteracts the acidity.

· To attempt to keep your soil acidic organically (beyond the organic fertilizers) try keeping a separate compost heap made of Oak leaves, used coffee grounds, Pine needles, and other green matter. Use this compost each spring on these plants. You can also make a Compost Tea from it to feed them periodically, like a liquid fertilizer. Continue to dump your used coffee grounds around such plants throughout the year, again being careful not to add too much.

Acid-loving Plants:

· Magnolias, Serviceberries, River Birch, & Clethra.

· Garden Lilies, Butterfly Weed, & Primrose

· Ferns and most Woodland Plants

· Hydrangeas, Blueberries, Hollies, Pin Oaks, & various other Evergreens.

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