Blood and bone, what it does and where not to use it

Blood and bone is the fertiliser most people reach for first, and for good reason. It is cheap, it is organic, and it does a real job on most of a garden. There are two things about it that nobody mentions on the bag though, and one of them will kill a plant while the other one will put your dog at the vet, so they are worth five minutes of your time.

What is actually in it

Exactly what it says. Dried blood, which is where the nitrogen comes from, and ground bone, which is where the phosphorus and the calcium come from. Nitrogen for leaf, phosphorus for roots and flowering, calcium for general plant structure.

It is a slow-release fertiliser and it is slow in the literal sense. Soil microbes have to break it down before the plant can use any of it, which takes weeks rather than days, and it happens faster in warm, damp soil than in cold, dry soil. So it is a fertiliser you put on before you need the result, not one you reach for when a plant is already struggling.

Where it works well

  • Digging a new bed over before planting.
  • Vegetables, especially the leafy ones.
  • Roses, fruit trees and most ornamentals.
  • Bringing a tired bed back before the next planting goes in.

Where it does not, and this is the bit that catches people

Do not put blood and bone on phosphorus-sensitive Australian natives. Banksias, grevilleas, hakeas and waratahs, and most of the rest of that family, evolved in soils with almost no phosphorus in them and they take it up far too efficiently. Give them a normal fertiliser and they will yellow off, drop leaves and often die, and it looks like neglect rather than the opposite.

Use a low-phosphorus native fertiliser on those instead. It is a specific product for a specific reason and it is not a thing shops invented to sell you another bag.

Not every native is sensitive, but the safe rule is that if it is in that family, feed it something made for natives.

Keep the dog off it

Blood and bone smells like food to a dog, because in a sense it is. Dogs dig it out of a fresh bed and eat it, and a dog that eats a decent quantity can end up seriously unwell with it.

So rake it into the soil rather than leaving it sitting on the surface, water it in afterwards, and keep the dog out of that bed for a day or two. Raking it in also cuts the smell down and stops it blowing off in the wind, so you would want to do it anyway.

Store the bag somewhere closed and off the ground for the same reason.

How to put it on

Spread it evenly at the rate on the bag, rake it lightly into the top of the soil, then water it in. That is the whole method. It is very hard to burn a plant with blood and bone the way you can with a concentrated synthetic fertiliser, but even coverage still beats a handful in one spot.

It is not a complete answer on its own. It is light on potassium, which is what fruiting and flowering plants want once they get going, so most gardens end up using blood and bone as the base and something else on top when the flowers appear.

Shop related products

Did you know we also keep Neutrog Bush Tucker, which is the low-phosphorus fertiliser for natives, plus a native planting mix and blood and bone in 2.5kg and 10kg, and not all of that is listed on the website. Give us a ring on (08) 8536 4333 or come in and we will point you at the right one for what you are feeding.

The rest of the garden range is on the website, and the garden centre carries a fair bit more again.

More from the garden

Still learning, still on first-name terms with a dog who thinks the veggie patch is a buffet. Candeece.

Follow our Facebook page: Strathalbyn H Hardware

Back to blog

More Gardening Greats

View all

Learn More

View all
1 4
View all