Blood meal feeds leaves. Bone meal feeds roots and flowers. Both are organic fertilizers made from animal by-products, but they supply different nutrients. Blood meal is rich in nitrogen and acts fairly quickly, so it is used to green up leafy growth. Bone meal is rich in phosphorus and calcium and releases them slowly, so it goes in at planting time to support roots, flowering and fruit.
Many gardeners use both, at different times. Here is how to tell which one your plants need.
Bone meal vs blood meal at a glance
| Blood meal | Bone meal | |
|---|---|---|
| Made from | Dried animal blood | Ground, steamed animal bones |
| Typical NPK | About 12-0-0 | About 3-15-0, plus calcium |
| Main nutrient | Nitrogen | Phosphorus and calcium |
| Speed | Relatively fast for an organic fertilizer | Slow, over months |
| Best for | Leafy growth, pale or yellowing plants | Roots, bulbs, flowering, fruiting |
| When to apply | Early to mid growing season | At planting or early in the season |
What blood meal does
Blood meal is one of the richest organic sources of nitrogen. Nitrogen drives green leaf and stem growth, so blood meal is useful for:
- Leafy vegetables such as lettuce, spinach and cabbage
- Plants with pale or yellowing older leaves, a common sign of nitrogen shortage
- Giving young plants a start once they are established
How to use blood meal
- Mix it lightly into the top few centimetres of soil and water it in.
- Use small amounts. Too much nitrogen can burn roots and produces soft, leafy growth with few flowers or fruit.
- Avoid heavy use just before flowering, and late in the season when soft new growth may be damaged by cold.
- In containers, use even less, because roots have less soil to buffer them.
The smell can deter some animals, such as rabbits, but may attract others, such as dogs. Working it into the soil helps.
What bone meal does
Bone meal supplies phosphorus, which supports root development, flowering and fruiting, and calcium, which helps build strong cell walls. It is useful for:
- Bulbs, such as tulips and daffodils
- Root crops, such as carrots, onions and potatoes
- New beds, transplants, shrubs and trees
- Flowering and fruiting plants
How to use bone meal
- Mix it into the soil or planting hole so it sits near the roots. Do not leave it on the surface.
- For bulbs, mix it into the soil at the bottom of the hole rather than letting it touch the bulb directly.
- One application per season is usually enough because it releases slowly.
A note on soil pH
Bone meal works best in neutral to acidic soil. In alkaline soils, above about pH 7, plants struggle to take up its phosphorus. If your soil is alkaline, or a soil test shows phosphorus is already high, bone meal will add little.
Can you use bone meal and blood meal together?
Yes. They complement each other: blood meal for nitrogen, bone meal for phosphorus and calcium. A common approach:
- At planting: mix bone meal into the bed or planting hole, with a little blood meal for leafy crops.
- Mid-season: if leaves turn pale, add a light dose of blood meal.
- Late season: stop using blood meal. Avoid encouraging new soft growth.
Neither supplies much potassium, the third main nutrient. Add a potassium source, such as compost, wood ash used sparingly, or a potash fertilizer, if your soil needs it. Blended “blood, fish and bone” products combine all three ingredients. See fish, blood and bone fertilizer.
Which one should you choose?
- Pale, slow-growing leafy plants: blood meal
- Planting bulbs, roots or new shrubs: bone meal
- Tomatoes and other fruiting crops: bone meal at planting, with nitrogen used carefully. See the best fertilizer for tomatoes
- Not sure: do a soil test first
Safety tips
- Store both in sealed containers, out of reach of pets. Dogs are drawn to them, and eating large amounts can make them ill.
- Wear gloves and avoid breathing the dust.
- Do not exceed label rates.
Buying in bulk
Agromer supplies blood and bone fertilizer in bulk to distributors and agricultural buyers. For shipment-size enquiries, tell us the product, quantity, packaging and destination. See blood and bone fertilizer bulk suppliers and our fertilizer range.
Frequently asked questions
What is the difference between bone meal and blood meal?
Blood meal is mainly nitrogen, for leafy growth. Bone meal is mainly phosphorus and calcium, for roots, flowers and fruit.
Which is better, bone meal or blood meal?
Neither is better overall. Use blood meal when plants need nitrogen and bone meal when they need phosphorus, usually at planting.
Can I mix bone meal and blood meal?
Yes. Many gardeners use both, often mixed into the soil at planting, to supply nitrogen, phosphorus and calcium together.
Is bone meal good for tomatoes?
It can help at planting by supplying phosphorus and calcium, as long as your soil is not alkaline and is not already high in phosphorus.
How often should I use blood meal?
Only when plants need nitrogen, usually once or twice early in the season. Overuse can burn plants and reduce flowering.
Is blood meal safe for pets?
It is not toxic in small amounts, but dogs may dig it up and eat it, which can upset their stomach. Work it into the soil and store it securely.