Tomatoes are a popular crop in gardens as they tend to be very easy to grow, but they are heavy feeders which means they need more nutrients compared to other plants.
Monty Don from Gardener’s World say that tomatoes will grow bigger and more delicious fruit if fed enough potassium, a crucial nutrient which is needed for fruit production.
The gardener also shared that you can easily make a homemade potassium fertiliser to help give crops a boost, and all you will need is one common garden plant.
Monty said: “Potassium is what plants need to form good flowers and fruit, and fruiting flowers like tomatoes and gooseberries have quite a high potassium demand.
“You can boost that at this time of year and improve fruit production. One way of doing that is to go to a garden centre and buy liquid or granular fertiliser, but there’s no need as you can also grow your own supply of potassium really easily through comfrey. “
Comfrey is a common garden weed known for its large hairy leaves which are very nutrient-rich in potassium and well as other nutrients tomatoes need such as calcium.
Monty said: “Its main use to me in this garden is to provide the raw material for a liquid feed that’s high in potassium.
He added: “A caution about comfrey is that once it gets established it has deep roots and it’s quite hard to get rid of. However, you shouldn’t get rid of too much as it really is so useful.”
How to make a homemade tomato fertiliser
You will need:
- Comfrey leaves
- Large waterproof bucket with lid
- Large stone to weigh on a bucket
- Plastic bottles such as old milk bottles
- Watering can
Method:
All you need to do is harvest comfrey leaves from the plant, but be careful as the leaves can irritate the skin so wear gloves if needed.
Remove flowers and stems from the comfrey and then chop up the leaves, pack them tightly into a waterproof container and then pour water on top of the leaves.
Once the bucket is filled, place the lid on the bucket and leave it somewhere safe in the garden for a few weeks to completely break down and liquefy.
Monty said: “The idea is to loosely fill a bucket or just put what leaves you’ve got, then put water in on top of that and leave it to brew for three weeks.”
Make sure to use a container with a lid and place a stone on top of the bucket as while comfrey is very good for tomato plants it is known to have an awful smell as it breaks down.
Monty said: “Then when it is properly made, it will form a black vile-smelling sludge, and I’m not exaggerating it smells disgusting…it’s covered not to protect the brew but to protect us from its vile smell.”
After around three weeks, check the comfrey mixture and it should have broken down into a smelly brown liquid. Then put the liquid in plastic bottles and store it in a cool, dark place.
Once you are ready to fertilise your tomatoes, stain the leaves and dilute the fertiliser at a rate of one part comfrey liquid to 10 parts water. The darker the fertiliser is the more it will need to be diluted.
Then place it in a watering can and use it to feed your tomato plants, where you will help give your tomatoes a boost to get bigger, juicer and better quality fruit for your next harvest.
