Monty Don reveals his secret one-ingredient homemade fertilizer for bigger, juicier tomatoes

Tomatoes are a popular crop in gardens as they are easy to grow, but as heavy feeders, they need more nutrients than other plants. Gardening guru Monty Don says that tomatoes given enough potassium will grow bigger and tastier fruit. The Gardener's World star says you can make a homemade potassium fertilizer to help give crops a boost, and all you 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 center and buy liquid or granular fertilizer, but there's no need as you can also grow your own supply of potassium really easily through comfrey. ", reports the Express .

Comfrey, a common garden weed known for its large hairy leaves, is packed with potassium and other nutrients tomatoes need like 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.

• Stop using vinegar to kill gravel weeds and use a better kitchen item that removes them 'forever'
• Garden hack using empty wine bottle is ‘most genius thing’ and will water plants evenly every time

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 fertilizer

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."

Give it roughly 21 days, and voila putrid brown potion awaits. Bottle it for later, keeping it cool and shadowed.

When your tomatoes are thirsty for strength, filter out the gunk and weaken this zesty tonic one splash of comfrey elixir to ten of water. Remember, the murkier it looks, the more you dilute.

Then, pour it into a watering can and use it to nourish your tomato plants. This will help your tomatoes grow larger, juicier, and of better quality for your next harvest.