Apply well-rotted manure to your New Zealand brass buttons early in the spring. Spread the material over the entire bed to a depth of 1 inch, just as with mulch. This supplies the plants with much of the nutrition they need for the entire growing season.
Feed brass buttons an all-purpose, liquid fertilizer in early spring before new growth emerges, once they become well established. Mix the material with water in a watering can according to the packaging instructions. The amount of packaged product and its correct mixing specifications vary according to the brand and type of fertilizer that you purchase.
Add an amount of water equal to the volume of the fertilizer mixture in the watering can to dilute it to half-strength. Blend the solution thoroughly.
Water your brass buttons' roots thoroughly with the solution.
Repeat the all-purpose liquid fertilizer application procedure once early in the summer.