Manure & Macronutrients for Dahlias
Manures & Macronutrients for Dahlia Excellence
Manure is an important part of soil building. It delivers nutrients, biodiversity, fungi, gut bacteria, ligin and of course fertilising macronutrients, commonly simplified as NPK. Manure varies considerably in its composition. Tim Marshall, a pioneer in Australia’s organic movement, and Australasia’s first certified organic farm inspector, published a useful analysis of manure NPK proportions averaged across multiple samples in three seasons:
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| Manure | N | P | K | Comments |
| Alpaca | 0.8 | 0.35 | 0.7 | very good easy to use manure, not hot and will not burn plants |
| Cow (dairy) | 0.9 | 0.45 | 0.7 | has few weed seeds will not burn plants |
| Horse | 0.7 | 0.25-0.4 | 0.4-0.6 | may contain weed seeds can burn sensitive plants when fresh |
| Pig (fresh) | 0.5-1 | 0.3-0.5 | 0.2-0.45 | usually only available in dried form or composted |
| Poultry (fresh) | 1.5-2.1 | 1-1.5 | 0.5-1 | may burn plants. compost prior to use |
| Poultry (dry) | 4.5 | 3.5 | 2 | may burn plants. compost prior to use |
| Rabbit | 2.4 | 1.5 | 1.8 | pellets are easy to handle |
| Sheep | 0.9 | 0.5 | 0.8 | pellets are easy to handle |
You may be tempted to add many things to your soil for your dahlias Be careful with:
Wood Ash: Easily overused. Will make soil more alkaline. Adds potassium and small amounts of magnesium and calcium. Excessive amounts will prevent uptake of other essential micronutrients.
Epsom Salts: Not a cure-all for nutrient deficiencies, gall or viruses. Epsom Salts contain magnesium and sulphur. Easily over applied. Apply when magnesium deficiency symptoms are present around the base of the plant. (These are easily confused with virus symptoms)
Blood and Bone: Fast vegetative growth, long weak stems, reduction of inflorescences. Easily over applied. Should be balanced with the carbon of at least one inch of medium bark mulch. Apply after when plants are at minimum 50cm tall. Sheep pellets applied over mulch are slower to release nitrogen and will retain moisture.
Text Copyright ©Joshua Hall. Extract from article in New Zealand Dahlia Society Magazine Autumn edition 2022