Garden botany

Don't worry if you skipped your science lessons at school as this is where you can quickly catch up – and get even more from your garden. Understanding how things work when it comes to your plants will inspire you to become an A* gardener. Quiet please - no talking at the back!


Check out the side panel on any box or packet of fertiliser. You will see a mysterious sequence of letters followed by numbers. It might look something like N: P: K followed by 10:10:10. What is this strange sign? NPK? What's going on?

It's really simple. The three main nutrients a plant needs are nitrogen, phosphorus and potassium. And guess what? Yep, the symbol for nitrogen is N, phosphorus is P and potassium has to be K. N:P:K – easy.

Now for the numbers. The number relates to the ratio of that particular nutrient in the mix. For example, if you see 10:10:10 you will have in your hands a balanced fertiliser. If you see 20:10:10 then the mix will have proportionally more nitrogen than the other two. Still with me? Good.

Each of those nutrients does different things to a plant. Nitrogen is the stuff that leaves dream of. Lush foliage = lots of nitrogen. Roots love a lot of phosphorous. And fruit and flower production is so much better for a diet rich in potassium (more commonly referred to as potash). So, if you want to green up your sad looking lawn within days, apply a fertiliser that is high in nitrogen. The same principle is happening when your dog has a wee on your lawn – urine is packed full of nitrogen and the leaves lap it up (of sorts). If you want to encourage your plant roots apply something higher in phosphorus. And if you want to help to produce strong flowers then potash is the key.

You can apply chemical fertilisers from a packet. You know exactly what is in the pack and what it will do. If you do this, only apply exactly what the manufacturer recommends as it is not a treat for your plants to overdose them on fertiliser. This could result in damage to leaves and roots.

However, a healthy soil doesn't really need additional fertiliser unless your plant is showing symptoms of nutrient deficiency. Think of what those key nutrients do – sickly looking leaves could be lack of nitrogen; poor root systems could be low phosphorus; and lack of flowers, or at least poor blooms, could just need a boost with potash.

But healthy soil that is balanced in these key nutrients is best achieved through fantastic microbial activity.  And the action of worms and all the other critters doing their bit of course. So, look closely at your plants. Study them, understand them and see how you can help them achieve their full potential. 

Friendly Fungi

Here at we all love a dusting of mychorrizal or friendly fungi. OK, maybe not on our porridge in the morning but certainly on the roots of most plants. And it's best applied at planting time. But really, what is happening once you have sprinkled the Empathy mychorrizal fungi onto the roots and plunged them into your fertile, deeply cultivated soil? Well, here's what...

A beautiful relationship immediately starts to blossom. It's one that would happen anyway; all you are doing is playing Cupid and putting the two individuals together. You are speeding up a natural process, making things happen where both the plant and the fungi benefit. The fungus attaches itself to the root. It then actually pierces the walls of the root and starts to grow inside. But don't panic (Mr Mainwaring) as the plant is fine with all of this. In fact, it is more than fine. The plant supplies a nibble of food for the fungus, and in return, the fungus, well, provides a shed load of goodness.

In return for that morsel, the fungus grows into the surrounding soil and sucks up more water and nutrients than the roots possibly can when acting alone. All of this is passed into the plant. Once inside the plant, the water and nutrients are put to good use – quicker establishment, stronger growth and, in subsequent weeks, better fruit, crops, flowering and seed production (all creating a better deal for us gardeners). The fungus continues to grow into the soil, multiplying as it goes, and will expand the capability of a root system by many times. That's why it is perfect to add at planting or sowing time. Imagine a tiny seed germinating and getting all the help it needs during its first minutes of life. Imagine a bulb pushing its first roots into an uncertain world and being welcomed with open arms (or fungal hyphae but let’s not allow technical terms ruin the image). Imagine the first nervous and tentative steps of a new root – so much easier and productive if helped along the way with a support network.

Now, all of this does happen naturally over time. You might not want to sprinkle a light dusting of friendly fungi and, instead, just let your new plants, seeds and bulbs get on with it. Survival of the fittest and all that. Or you could be the caring gardener and speed up this natural process. Gardening is a game of patience, but if you want to get the best from the plants you grow then play Cupid and get your bow and arrow out -or a sachet of Empathy mychorrizal fungi - and get sprinkling. 

Check out Phil's video all about mychorrizal fungi below:

What happens when you prune?

There's one piece of gardening advice that crops up time and time again. 'Nip out the growing point to encourage bushy growth'. It's a basic form of pruning and chances are you've done it to your fuchsias and pelargoniums to prevent one shoot from growing away to eventually produce a lanky plant. Get nipping and you will end up with a bushy specimen. But what is actually happening when your thumb and forefinger spring into action?

We are into the murky world of hormones. Yep, plants have them in the same measure as teenagers and the growing tips of shoots have lots. Think of a shoot tip – the main shoot on your plant. That tip is producing and pumping down a plant hormone called auxin. It inhibits the growth of buds lower down – that shoot tip is top dog and won't let anything take its limelight. Get rid of it and suddenly the side shoots beneath are allowed to grow. So instead of one shoot growing tall, you then have side shoots growing. Let them grow a bit and their own leading shoot pumps out auxins to lower shoots and prevents them from growing. Nip out the new leader and, hey presto, the next set of side shoots are allowed to grow. Allow them to grow a bit and then… you get the idea.

So, it's all down to plant hormones. Remove the source of auxin at the top and lower shoots will grow. Simple but clever!