- In mature hostas, forgetting to feed will not make a huge difference. How much to fertilize your hostas depends on your garden situation, because healthy plants need a balance of light, water, nutrients and the proper soil. Hostas that are constantly moist may require more nitrogen as nitrogen will leech (wash out) of the soil. Sandy soils will leach nutrients faster than more clay or humus soils. If your garden is in deep shade, more fertilizer might not be the solution to increase the plant size or growth rate because the problem is insufficient light. Overall, fertilizing can provide hostas with a boost in nutrient-poor soil.
Tom Carlson’s fertilizing video explains some of the best hosta fertilizer hardware and how to use it. See the hosta videos page for more HostasDirect Productions.
Fertilizers come in liquid feed, granular and slow-release. Liquid hosta fertilizer is ordinary garden fertilizer such as Peters, Shultz or Miracle Grow that can be drenched into the soil or sprayed on the leaves as a foliar spray. Drenching the soil is more effective but is harder to do after the hostas unfurl. Standard 10-10-10 inorganic garden fertilizers are quite inexpensive. However, the nitrogen can leach out of the soil fast depending on the amount of water applied and soil type. Do not let granular fertilizers remain on hosta leaves as they can burn small holes in the leaves. It is important not to fertilize hostas past late-July, as the plants should not be over-stimulated to make new growth. In Minnesota, using a time and temperature released fertilizer may create problems. Some types of hosta fertilizer require a temperature of 70 to 77 F. to start releasing fertilizer into the soil and will release fertilizer for 60, 90 or more days, which releases fertilizer in August. This can be harmful. Fertilizing hostas after July 31 may promote soft, sappy growth that slugs and snails will appreciate. Hostas need to slow down in the fall and harden off for winter. High nitrogen fertilizers that are often used for lawns such as 30-0-5 can produce tremendous growth, but may make the plants more susceptible to various fungal and bacterial rot. Osmocote has many different time release products that are excellent.
Foliar hosta fertilizers are liquid fertilizers which are absorbed through the leaves and roots. Foliar fertilizer needs to be applied every two to three weeks during the growing season if not weekly since it remains in the root zone for shorter periods of time than soil-fed fertilizers.
These fertilizers are absorbed through the soil.
Organic fertilizers have lower analysis numbers than inorganic fertilizers and, therefore, tend to burn less. However, you will need to apply them more frequently to get the same amount of nutrients. They may also attract voles.
BE CAREFUL! Some manure is full of weed seed that will create extra weeding for you. Make sure the manure is well-rotted so it does not burn the plants, and it is also free of weed seed. This is tough to guarantee. If you do find good manure, it can really make your hostas grow with low maintenance as it breaks down, naturally fertilizing hostas . for years.
Kill all weeds before planting. We like Roundup and recomend our premium garden weeding tool to quickly pull weed roots out of the soil. Be sure to continue to weed frequently in order to eliminate weeds from ever going to seed. If you do this, you will find your hostas will keep out most weeds because they create so much shade and your garden will be low-maintenance, look beautiful and be much less work grass. Again, do not let weeds go to seed!
Some gardeners use Preen in the spring. Preen is a granulized, pre-emergent weed killer, which is compatible with hostas. Some use Round Up, which will kill anything green, so be careful. Some use a combination of both.