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.
Janilyn Ward Layton Anywhere from once a week to 2-3 times a week, it depends on how busy my french press is! But I've been adding coffee grounds to the soil ever since I moved in to my house in Fall 2021 — these hydrangeas were planted by the previous homeowner. Kim Fitz they don't appreciate Oak leaf hydrangeas.
The Short Answer
Once established, hydrangeas should be watered about one inch per week, spread across 3 watering sessions. The water should be evenly distributed at the roots, and never over the top of the plant. Watering top down will encourage fungal disease, and potentially harm the plant.
Salts: Coffee grounds can contain salts, which can build up in the soil over time and become toxic to plants. Mold: Wet coffee grounds can attract mold, which can be harmful to plants. Caffeine: While caffeine is not toxic to plants in small quantities, it can be harmful if used in large amounts.
Avoid using coffee grounds on alkaline-loving trees, such as linden, ironwood, red chestnut and arborvitae. Coffee grounds used as mulch or compost inhibit plant growth on geranium, asparagus fern, Chinese mustard and Italian ryegrass. Definitely don't use coffee grounds with these plants.
Coffee grounds can most certainly be added to your compost and also directly to your soil. Instead of simply tossing them out though, you may wish to incorporate them a bit more thoroughly by digging them in.
To turn hydrangeas blue, you'll need to make your soil more acidic. You may have heard of tricks like adding coffee grounds, vinegar or even pennies or a bundle of rusty nails to the soil. However, it's best to use aluminum sulfate, which is a proven method for changing flower color.
Coffee-Loving Plants and Vegetables
Generally, plants that prefer acidic soil respond well to a weekly watering with coffee or a sprinkling of coffee grounds. However, there is a difference between plants that prefer slightly acidic soil and. plants that need very acidic soil.
Plant Nutrition
We recommend feeding Hydrangea with a slow-release, granular fertilizer such as Plant-tone® + Iron-tone® OR Holly-tone® + Iron-tone® in both spring and midsummer. For a bloom boost, try applying Triple Phosphate, per package instructions, in addition to fertilizer.
What do overwatered hydrangeas look like? Hydrangeas that have been overwatered will likely have fewer blooms and wilting leaves and flowers. The leaves may also turn yellow and feel soft and squishy.
Newly planted hostas will need bi-weekly watering for the first month after planting. Once established, small or medium plants will need a good soak about once a week. Hostas are drought tolerant yet like moist, well-drained soil. If the weather is hotter, increase the watering to two times per week.
Cover the soil around the plant's trunk with well-dried coffee grounds and water abundantly. Each watering will release nitrogen from the coffee grits and penetrate into the soil with water, soaking the plant's root system, thereby strengthening it and protecting it from pests.
Most common hydrangeas prefer a partial sun location - ideally receiving sun in the morning hours and shade in the afternoon. The reblooming Endless Summer® Hydrangea series prefers part shade. These include BloomStruck®, Endless Summer®, Blushing Bride®, and Twist-n-Shout®.
Amending soil with coffee grounds improves water retention, enhancing the health of moisture-loving plants such as bleeding heart, canna lily, cardinal flower, hosta, primrose, and spiderwort. Avoid using grounds in waterwise landscapes or around low water plants.
Excess coffee grounds, if applied to the soil before composting, have multiple effects on the soil system. In addition to microorganisms tying up nitrogen temporarily, the caffeine residues in the spent coffee grounds can suppress germination and slow the growth of some plants.
Which plants like coffee grounds? Especially plants that like acidic soil are very happy with coffee grounds. For example, your beautiful hydrangeas, your radiant roses, the lawn or the lavender bushes, but also the gardenia, chamomile and rhododendrons.
We recommend using about a teaspoon of coffee grounds per gallon of water. Let the coffee grounds and water mixture steep for a few nights, stirring occasionally, then strain the liquid through a cheesecloth. The remaining liquid can be used to water, and gently fertilize, your houseplants.
Turning your hydrangea flowers pink is achieved by adding lime to your soil. Apply garden/agricultural lime by following the recommended dose for the product you purchase. The dose can vary depending on your current pH and the type of soil you have. Sandy soils require less lime than clay soils.
Removing the spent blooms triggers flowering shrubs to stop producing seeds and instead put their energy toward root and foliage development. This makes plants stronger and healthier, so by deadheading, you'll be doing your hydrangeas a favor.
A little fertilizer goes a long way when you're trying to score bigger hydrangea blooms. Becker recommends a "bloom booster" fertilizer with a high level of phosphate, like osmocote (14-14-14).
However, there are some plants that you should avoid using coffee grounds on. Plants that prefer alkaline soil, like lavender and lilacs, can be harmed by the acidity of coffee grounds. Plants that are sensitive to caffeine, such as geraniums and some herbs, can also be affected by the presence of coffee grounds.
Eggshells used as fertilizer for your garden can benefit the soil your plants use to gain essential nutrients, aiding rapid growth and keeping soil acidity in check. Here's how and why you should put your eggshells to use in the garden the next time you make an omelet instead of simply tossing them in the trash.
Which plants benefit from used coffee grounds? Coffee tends to be slightly acidic and is therefore good for acid-loving plants such as hydrangeas, as well as nutrient-hungry plants like roses, but again use it only in moderation on any one plant.