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If you’re a home gardener who’s looking to add some hostas to your landscape, you’ll need to know how to prepare the soil properly.
Hostas grow best in sandy loam soil that’s rich in organic matter. Hostas prefer a slightly acidic soil pH, with a pH level of 6 being optimal. The soil should have good drainage and be kept consistently moist while allowing excess water to drain away easily. Soil amendments like compost and rotted manure can help with nutrient content and tilth, while mulch can help keep the soil moist and cool during the growing season.
Read on to learn all about soil for hostas!
The best soil for hostas
The best soil for hostas is moist sandy loamy soil with a slightly acidic pH level. These plants also grow best in soil with good drainage, as they require soil that is moist but not overly wet or muddy. Many hosta gardeners start with their native garden soil and amend it with organic matter and potentially adjust the pH levels to a slightly acidic level. Slow-release fertilizers are also popular for spectacular hosta foliage.
To ensure your hostas and other shade perennials have the best soil conditions, you need to know what you’re starting with. Get a soil test done before planting your hostas to get an idea of current pH levels, organic matter percentage, and nutrient levels. Most laboratory-quality soil tests include individualized recommendations for soil amendments based on your soil sample and the type of plant you’d like to grow (like hostas in this case).
Here are some of the most popular amendments used to create great soil for your hostas:
- Organic compost (homemade or storebought)
- Coco coir or peat moss
- Perlite or vermiculite
- Natural soil acidifier (sulfur, gypsum)
You can also use a potting mix to amend the soil for hostas provided it is a high-quality mix that includes some of the above ingredients. The best potting mixes for hostas and other shade-loving perennial plants are generally made with a mix of coco coir and/or peat moss for bulk and moisture retention plus perlite for air entrainment and some organic compost for plant nutrients and soil tilth.
Hosta soil requirements
Hostas do not have strict soil requirements and are tolerant of both heavy clay and overly sandy soils. That said, they tend to thrive in friable balanced sandy loam soil that contains adequate organic matter for healthy soil tilth and nutrients. While hostas are tolerant of alkaline soil, they grow best in slightly acidic soil levels.
The soil needs to hold enough water to support healthy growth while allowing excess water to drain away from the roots. Hostas are only tolerant of ponded water for a short amount of time, so avoid planting them in a low spot in clay soil where water pools after rainfall.
Preparing soil for hostas
If you’re starting with native garden soil, the best way to prepare it for hostas is to first do a soil test. This will give you an idea of your current pH levels and nutrient content so you can make the necessary adjustments before planting. Soil tests are generally done in the early spring in time to prepare for the upcoming growing season.
Once you have your soil test results, you can start preparing the soil by adjusting the pH levels and adding organic matter as needed. You can also add a slow-release fertilizer to provide nutrients throughout the growing season. Here are some options for each of these amendments:
Soil amendments for adjusting pH
Hostas grow best in slightly acidic soil with a pH of 6 being optimal. That said, hostas can generally grow perfectly well in a pH range from about 5 to about 7.5 if other environmental conditions are good. Here are the most common soil amendments for adjusting pH:
- To lower a neutral or alkaline pH down to 6, use a natural soil acidifier like sulfur or gypsum
- To raise a very acidic pH up to 6, use an alkaline amendment like garden lime.
Soil amendments for adding organic matter
Hosta roots prefer rich soil that contains a high percentage of organic matter. As this is uncommon in most residential gardens, many gardeners choose to incorporate additional organic matter into their soil, including options like
- Homemade compost
- Store-bought compost
- Rotted manure
- Coco coir
- Peat moss
Slow release fertilizers for hostas
Hostas are heavy feeders that often require added mineral nutrients to grow and put on their best show of summer foliage. This is especially true of cultivars with dark green, matte blue, yellow, or chartreuse leaves (especially if the leaves have variegation). Some varieties also have showy bell-shaped blooms that benefit from added fertilizer. Here are some good options for hosta fertilizer:
- Espoma Holly-Tone Slow-Release Fertilizer
- Down to Earth All Natural Acid Mix Fertilizer
- Organic Blood Meal (naturally high in nitrogen)
- Bone Meal (naturally high in phosphorus)
Most fertilizers with a balanced ratio of nitrogen, phosphorus, and potassium (plus micronutrients) will work well for feeding hosta plants.
How to prepare the soil for hostas?
Here are the basic steps for preparing the soil for planting hostas. These steps apply to moist soil textures, including heavy clay soil or overly sandy nutrient-poor soil.
- Research the mature size of the hosta variety. A miniature hosta can be less than a foot wide at maturity while larger species of hosta plants can be 6-8 feet wide in diameter in under a decade.
- Clear out any existing plant debris from the expected mature footprint of the plant, including pulling out any weeds and digging out any large roots. Clear an area wide enough to accommodate the mature diameter of the foliage rather than just an area big enough for a planting hole.
- Dig the soil down to 12-18 inches to loosen the existing native soil. Loosen an area at least as wide as the expected mature spread of the hosta leaves, as the roots generally spread at least as far as the aboveground portion (if not wider). Take note of the natural moisture level of the soil and make sure to break up any large clumps of soil.
- Mix in a soil amendment rich in organic matter like compost (see more options for organic materials listed above). You may also wish to mix in a pH adjuster like soil acidifier, as well as some starter transplanting fertilizer like Bio-Tone Starter Plus.
- Remove excess soil from the area and rake the amended soil bed flat.
- Give the whole prepared planting area a thorough deep watering. Check with a shovel to see that the water is penetrating to a depth of at least 6″ into the prepared soil bed.
- Plant the hosta in the prepared garden bed. Mulch the soil with an organic mulch after planting the hosta.
Mulch for hostas
Mulch is also an important part of preparing the soil for growing healthy hostas. A good organic mulch helps keep the soil moist during hot weather and protects the roots from rapid temperature swings such as early or late frosts. Organic mulches also provide a gentle stream of nutrients to the hosta roots as they break down into humus on top of the soil. Hosta beds are generally mulched in the spring and again in autumn.
Here are some good options for organic mulch to cover the soil around hostas:
- Leaf mold
- Wood chips
- Bark mulch (such as pine bark)
- Pine needles/pine straw
- Shredded leaves (if slugs are not too common)
A 2-3 inch layer of organic mulch-like leaf mold compost will help keep the soil moist and cool during the hot days of summer and hopefully protect against overly cold temperatures and temperature swings during shoulder seasons. Mulch also keeps weeds down and creates a cleaner look during the cooler months when hosta foliage has been cut back. Avoid using shredded leaves as mulch if pests like slugs and snails are common, as they seem to like to live in shredded leaves (and also love to eat hosta plant stems and leaves).
Soil for hostas growing in containers
Hostas in pots grow best with a high-quality organic potting mix that contains coco coir or peat moss for bulk, perlite or vermiculite for air pockets, and organic compost for tilth and plant nutrients. Most hostas grown in pots are smaller cultivar options, ranging from mini hostas to medium-sized hosta varieties. Here are some great potting soil options for growing hostas in pots:
- Espoma Organic Potting Mix
- Nature’s Care Organic Potting Soil
Large and giant hosta varieties are rarely grown in pots, but if they are, the soil mix generally includes some native topsoil (and the pots must be very wide!)