SUPERthrive is another product claiming great results for plant health without being a fertiliser. I’m not sure why these companies find it so offensive for their products to be known as fertilisers! Fertiliser just means a product containing plant nutrients. Anyway, what is in SUPERthrive? Here is the ingredient list:

So to start with – it *is* a fertiliser (1:1:1). Aside from nitrogen, phosphorus and potassium it also contains another macronutrient – calcium, and a micronutrient – iron. I’ve taken the explanation of these below from my post What each nutrient does (x17).

Calcium is used for plant structure as it strengthens the cell walls in plants. Its presence (or absence) is also used for signalling of stresses to the plant, allowing it to activate defences against pathogens. There is twice as much calcium in this product than N P or K – so quite a lot.

Iron is present in a large number of different enzymes within plant cells, appearing in chloroplasts (where photosynthesis takes place), mitochondria (where energy is created) and the cell compartment. Iron is therefore a key nutrient for growth and survival in plants – in just the same way it is with humans and other forms of life. Iron is a component of so many enzymes that there is a specific name for them – ‘FeRE’ or iron requiring enzymes (Fe is the chemical symbol for iron).

Iron can be toxic if too much is present, so plants have evolved mechanisms to remove it when it gets too high. There is a much smaller amount of iron than other nutrients in SUPERthrive.

SUPERthrive also contains four varieties of mycorrhizae (fungus which integrates with plant roots). The types included are all arbuscular mycorrhizal fungi which are a form of endomycorrhizae – that is, the fungal cells enter the plant’s roots. This supports healthy root development, improved access to soil nutrients and healthier trees. You can find these mycorrhizae in soil, particularly in established forests. Whether or not a specific type of mycorrhizal fungus will benefit your tree depends on the species of tree. There is a list of which types work with with species on this site.

From a bonsai point of view this list helps us see that endomycorrhizae (ie. the fungi in SUPERthrive) are not associated with plants in the families Pinaceae (fir, cedar, larch, spruce, pine, hemlock) and Fagaceae (beech, chestnut, oak), neither should they work for lime trees (Tilia).

They are associated with plants in the families Cupressaceae (cypress, juniper, redwoods, thuja), as well as acers, ginkgos and most other flowering trees. So you might see a difference in effect depending on the species of tree with which you use this product.

The final ingredient in SUPERthrive is humic acid. Leonardite, the source of the humic acid in this product, “is an oxidized form of lignite, very enriched in HS [humic substances] and characterized by well-known auxin-like effects”ref Lignite is a form of brown coal, which used to be peat but hasn’t become coal yet. Humic acid is a liquid made by dissolving leonardite, so it contains dissolved, concentrated organic matter (dead plants), effectively this is like super-concentrated liquid compost. Could it be similar to compost tea? In fact, yes, liquid from compost has also shown the same auxin-like effectref. Peat analysis shows a chemical composition of carbon, oxygen, hydrogen, nitrogen, sulphur in decreasing order.ref But this doesn’t tell the whole story. Peat and its compressed descendants contain a multiplicity of nutrients as well as other components – basically it’s all the ingredients which go into plants, and are synthesised by plants, compressed and starting to decompose. So this component of SUPERthrive probably has most of the nutrients required for plant growth – although these aren’t necessarily bioavailable. This study found that “Leonardites did not affect significantly any measured variables in comparison to the control”ref So my guess is that if you are fertilising your trees with a comprehensive fertiliser, and giving them some organic matter, the addition of humic acid may not make a difference.

Leonardite is mined in open-cut mines, and can be extracted using chemicals, so it’s not particularly environmentally friendlyref, nor sustainable as claimed by this manufacturerref, since it takes 300 million years to create!

Ultimately this product is a fertiliser with extra calcium, mycorrhizae to promote healthy root development (but only for certain tree species), and concentrated liquid compost/organic matter. It probably provides beneficial compounds to bonsai trees – particularly those in families which benefit from endomycorrhizal fungae. But I’d argue these compounds could be obtained elsewhere – from a comprehensive fertiliser, compost tea and a handful of humus (dark, organic material that forms in soil when plant matter decays) from your local forest. It’s probably a useful product though if you don’t have the time or access to other additives for your bonsai.