Fertilizer for Hostas: Do You Need It, and Which Kind
University of Georgia Extension says hostas “respond best to light fertilization”, and several extension services say to fertilize only if a soil test shows it is needed. In a bed that gets compost or leaf mulch every year, the answer is often that you do not need fertilizer at all. If you do, the amount of nitrogen and the timing matter more than the brand. This guide compares four common types from their labels.
How to choose
- Test the soil first. Minnesota Extension suggests a soil test every 3 to 5 years and, if it shows fertilizer is needed, applying it twice in the season. Georgia Extension also bases lime and fertilizer on a soil test.
- Keep nitrogen low. Nebraska Extension: “No more than one-eighth pound of actual nitrogen is needed for a 125-square-foot bed of hostas.” Too much gives soft foliage that wilts easily, invites leaf disease and can weaken variegation.
- Feed in spring, stop by the end of July. Minnesota Extension: apply first as leaves emerge and once more before flowering, then stop after the end of July so the plant can prepare for winter.
- Prefer slow release. Clemson and Nebraska recommend a slow-release fertilizer as growth begins. On the label, look at how much of the total nitrogen is “water-insoluble” or “slowly available” (Clemson explains how to read the guaranteed analysis).
- Read the “derived from” line to tell organic, biosolids and synthetic products apart (Clemson).
- Check organic claims. “Organic” on a bag is not the same as an OMRI listing; search the OMRI database if it matters to you.
How much product is one-eighth pound of nitrogen?
Using Nebraska’s figure for a 125 sq ft bed (our arithmetic, from the nitrogen percentage on each label): about 2.5 lb of a 5% product, about 2 lb of a 6% product, or about 0.5 lb of a 24% product. That is less than several of the label rates in the table.
Comparison
| Product | N-P-K | Nitrogen release | Derived from | Label rate (beds/perennials) | Feeds for (maker) | OMRI |
|---|---|---|---|---|---|---|
| Espoma Organic Plant-tone 5-3-3 | 5-3-3 | 3% of 5% N water-insoluble (slow) | Feather meal, poultry manure, bone meal, alfalfa meal, greensand, sulfate of potash | 4 lb per 100 sq ft (beds); 1 cup per established plant | Monthly schedule on label | No listing found |
| Milorganite 6-4-0 | 6-4-0 (+2.5% iron) | 4% of 6% N slowly available | Biosolids | 2.5 lb (7.5 cups) per 50 sq ft | Up to 10 weeks (5 lb bag) | Not listed |
| Miracle-Gro Water Soluble All Purpose Plant Food 24-8-16 | 24-8-16 | Water-soluble (fast) | Ammonium sulfate, urea, potassium phosphate, potassium chloride, micronutrients | 1.5 tbsp per 1.5 gal water, every 7–14 days | 7–14 days | Not applicable (synthetic) |
| Controlled-release coated granules (e.g. Dynamite Flower & Vegetable 13-13-13) | 13-13-13 | Polymer-coated, controlled release | Ammonium nitrate, ammonium and calcium phosphates, potassium sulfate and nitrate (older MSDS) | 2 Tbsp per sq ft broadcast | Up to 9 months | Not applicable (synthetic) |
Products
Espoma Organic Plant-tone 5-3-3
A granular organic fertilizer made from feather meal, poultry manure, bone meal and other natural materials, with added soil microbes.
Suits: Gardeners who want an organic, slow-acting feed applied once in spring and once before flowering. Three of its five percent nitrogen is water-insoluble (slow-release).
Limits
- The label's schedule is monthly through the growing season; Minnesota Extension advises stopping hosta feeding after the end of July.
- The bag says "organic" and the maker says "Organic Approved" without naming the certifier; we found no OMRI listing for Espoma or Plant-tone.
What we could not confirm
- Coverage per bag is not stated; at the bed rate of 4 lb per 100 sq ft, a 4 lb bag covers about 100 sq ft (our calculation).
Sources: Espoma Plant-tone product page ; Plant-tone fact sheet (PDF)
Amazon listing checked 2026-10-05: “Espoma Organic Plant-Tone 5-3-3 Natural & Organic All Purpose Plant Food; 4 lb. Bag; The Original Organic Fertilizer for All Flowers, Vegetables, Trees, and Shrubs.” (ASIN B001R4OJRS)
Check on Amazon Affiliate link
Milorganite 6-4-0
Kiln-dried pellets made from the microbes of the Milwaukee sewage treatment process (biosolids). Nitrogen and phosphorus with iron, and no potassium.
Suits: A slow-release nitrogen top-up in spring where a soil test shows potassium is adequate.
Limits
- No potassium (0%).
- The maker's perennial schedule includes a mid-summer dose; for hostas, apply it before August (Minnesota Extension).
- The maker says it is not sold in Connecticut and Maine, which ban land application of fertilizers containing trace PFAS.
- Earthy odour after spreading that, per the maker, fades within a few days.
What we could not confirm
- Coverage of the 5 lb bag: the maker gives no square-foot figure; at the perennial rate of 2.5 lb per 50 sq ft it is about 100 sq ft per application (our calculation).
Sources: Milorganite products ; Milorganite flower application rates ; Milorganite FAQ (state restrictions)
Amazon listing checked 2026-10-05: “Milorganite All-Purpose Eco-Friendly Slow-Release Nitrogen 6-4-0 Fertilizer, 5 Pound Bag - for Lawns, Flowers and Gardens” (ASIN B000UOB1P4)
Check on Amazon Affiliate link
Miracle-Gro Water Soluble All Purpose Plant Food 24-8-16
A synthetic fertilizer dissolved in water and poured at the base of plants. All of its nitrogen is fast-acting.
Suits: Hostas in containers, where nutrients wash out with watering, or a one-off correction in the ground.
Limits
- The highest nitrogen here, applied every 1–2 weeks by the label — Nebraska Extension warns that excess nitrogen gives soft foliage prone to wilting and disease, and can dull variegation.
- The label allows feeding any time in the growing season; for hostas, stop after July (Minnesota Extension).
What we could not confirm
- We read the label for the 5 lb box (about 2,000 sq ft); the maker gives no coverage for the 1.5 lb size.
Sources: Miracle-Gro product page ; Miracle-Gro label (PDF)
Amazon listing checked 2026-10-05: “Miracle-Gro Water Soluble All Purpose Plant Food, 1.5 lb.” (ASIN B000HACFUQ)
Check on Amazon Affiliate link
Why there is no controlled-release pick
Coated controlled-release granules are convenient — one application in spring — but the one we could source, Dynamite 13-13-13, feeds for up to nine months by the maker’s own description. That runs well past Minnesota Extension’s end-of-July cutoff for hostas. Its Amazon listing also does not state the 13-13-13 formula, so we could not confirm the listing matches the product we read about. We could not reach a current label for Osmocote from the manufacturer.
When you do not need to buy anything
- The soil is already rich. Oregon State’s Ask Extension: “Most plants do not need fertilizers if the soil is healthy”, suggesting up to an inch of mature compost in spring and fall instead.
- Compost and leaves do the job. Minnesota Extension says hostas prefer rich, moist soil high in organic matter, and that compost, composted manure or leaves improve soil structure.
- Pale leaves in deep shade. Iowa State notes that gold-leaved hostas are often yellow-green in partial to heavy shade — a matter of light, not feeding. A soil test, not leaf colour alone, tells you if nutrients are short.
- It is August or later. Skip feeding until spring (Minnesota Extension).
Soil tests are offered by state university labs, for example Penn State’s Agricultural Analytical Services Lab; your county extension office can tell you which lab serves your state.
Sources
- University of Minnesota Extension, Growing hostas in Minnesota (read from an archived copy of 2025-12-20).
- University of Nebraska–Lincoln Extension, NebGuide G1683.
- University of Georgia Extension, Circular 955.
- Clemson HGIC, Hosta and Reading a fertilizer label.
- Ask Extension, answer from Oregon State University Extension on fertilizing.
- Iowa State University Extension, All about hostas.
- Product labels, fact sheets and pages as linked in each card. Checked 2026-10-05.