You can use vinegar to lower the pH of your soil, but be aware that in order to achieve blue blooms, you will need both an acidic environment and aluminum ions. The acidic environment will also need to be a sustained over a period of time, which could be hard if rainwater is washing the vinegar away.
A pH of 7 is neutral, and household vinegar has a pH of around 2.4 (which is quite acidic). The theory is, applying diluted vinegar to the soil will lower the pH enough to change the color of your hydrangea blooms. This strategy will make the soil more acidic, but not for long!
To start "blueing," most hydrangeas need a pH level of 5.5 or lower. To make your soil more acidic, dilute 1 cup of apple cider vinegar into about 1 gallon of water. If you're fresh out of apple cider vinegar, you can also use white vinegar, but be aware that white vinegar tends to be much stronger.
Mix one cup of apple cider vinegar with 10 litres of water (an average watering can's worth) and direct the solution at the base of the hydrangea, avoiding the leaves. Do this every couple of weeks and the colour will gradually change.
Some gardeners report success in turning their hydrangeas blue by applying coffee grounds to the soil. The coffee grounds make the soil more acidic, allowing the hydrangea to more easily absorb aluminum. In addition, fruit peels, lawn clippings, peat moss and pine needles, are thought to have a similar effect.
Make a vertical slit in the incision and hold the stem upright in the boiling water for about 60 seconds. Place the hydrangeas back in your floral arrangement and they should revive themselves in an hour or so.
Homemade compost is a great source of slow release nutrients for hydrangeas. Either top dress the soil beneath your plants with your compost and water well or brew up a batch of compost tea and give your plants a deep drink of it. You can repeat your application of compost tea in 2 to 3 weeks.
Pickle juice is mostly composed of vinegar, which can help to lower the pH of the soil and make it more acidic, which can be great for plants like Hydrangea, Gardenia, Camellia, Azalea, Begonia, Impatiens, Rhododendron, Blueberry, Potentilla, Heather, Vinca, Clematis, Fuchsia, and Astilbe.
Place the hydrangeas on the cutting board and use the sharp knife to cut the end of the hydrangea at a 45 degree angle. Then cut a small slit vertically up the middle of the newly trimmed stem. Place the hydrangea(s) in the vase filled with hot water. Let sit for a minimum of one hour and voila!
Make sure you water the plant with diluted apple cider vinegar or white vinegar, and ensure you only water the base of the plant, as the acid could burn the leaves. You will need to continue watering the plant with diluted vinegar for several months before you will see results.
Espoma Organic Traditions 6 lb. Garden Sulfur Soil Acidifier is an all-natural mineral that can be used to lower the pH of your soil. It can also provide plants with sulfur, a nutrient that promotes growth and dark greening. It will turn hydrangeas from pink to blue.
For true blue flowers, the hydrangeas need to be grown in acidic soil with a pH of 5.5 or lower. For pink flowers, the plants need neutral to alkaline soils (pH 6.5 and higher). For purple blooms (or a mix of blue and pink flowers on the same plant), the pH of the soil must be between pH 5.5 and 6.5.
Use vinegar diluted with water in a ratio of 20 parts water to one part apple cider vinegar. Water the plants along their base. Try not to get the vinegar-and-water solution onto the leaves, because it can burn the foliage.
'Using compost tea is an accessible way to treat brown spots quickly and effectively,' adds H&G's garden expert, Rachel Crow. 'If you face these spots – whether from Cercospora or lack of sunlight – this trick will cure your plants back to health.
If your hydrangeas do get infected, you have several easy, effective, and homemade options. You can dilute either hydrogen peroxide or garlic oil in a spray bottle and spray it directly on the affected leaves.
Hydrangeas produce a “sap” that clogs their stems and blocks water from traveling up it to those gorgeous blooms. The boiling water helps to do away with the sap.
First, add a 1/4 cup of sugar to the room temperature water in the vase. The sugar helps feed the stems and increases the life of the cut flowers.
Miracle-Gro Performance Organics Blooms Nutrition
This is an all-purpose blossom booster that's suitable for use on a wide variety of perennial and annual blooming plants, including hydrangeas. It provides various minerals, including copper, calcium, and iron, to supplement common nutrient deficiencies.
Add lime to the soil for pink blooms; add aluminum sulfate for blue blooms. The amount of lime or aluminum sulfate needed depends on the soil composition.
In addition to bolstering future blooms and strengthening stems, deadheading your hydrangeas has aesthetic benefits, too. "Removing faded flowers creates a neat and tidy appearance, which many gardeners prefer over the look of leaving dried flowers on the plant," says Meyers.
Start adding coffee grounds to the soil surrounding your hydrangeas in late fall. Sprinkle them around your hydrangeas, but be sure to work them into the soil to help eliminate any off-putting smell. You do not need to do this process often–just two to three times per year should be sufficient.
Hydrangea Care Tips
Water at a rate of 1 inch per week throughout the growing season. Deeply water 3 times a week to encourage root growth. Bigleaf and smooth hydrangeas require more water, but all varieties benefit from consistent moisture.