Soil must be kept well stocked with nutrients for your vegetables to thrive but making your own plant food is easy, writes Michael Kelly
Nettle-tea feed will smell foul but is dynamite for plants as it's full of nutrients
"What's your record for consecutive questions asked?" asks Candy.
"38", replies Culkin. "I'm a kid. That's my job."
I was reminded of this the other day while being relentlessly questioned by my six-year-old son Nicky as we worked side by side in the polytunnel.
While I busied myself with planting, he was watering. Watering plants is the perfect job for a six-year-old. Operating the hose is a source of endless fascination and almost by accident, the watering gets done.
The torrents of water were accompanied by a torrent of questions. At one stage he was asking me why plants need water, and I told him that, like him, they need water to drink.
"They're very thirsty Dad?" he asked.
"Very thirsty," I replied.
"And what about food? What do they eat for breakfast?" he asked.
I told him that a plant's favourite thing to eat is compost, and I could see his eyes go wide as he imagined himself eating gloriously dirty handfuls of compost instead of porridge.
Perhaps on some level he also finally understood why his Dad spends so much time in the compost corner, tending to it like a man obsessed.
The act of growing a vegetable plant depletes the available food in the soil.
This must be replaced, or eventually the soil (and by extension the plants and people that live off it) becomes deficient in important nutrients.
The three main nutrients in question are the holy trinity of nitrogen, phosphate and potassium.
Interestingly, the different nutrients do different things for the plant.
The plant uses nitrogen for its leaves, phosphate for its roots, and potassium to produce fruits and flowers. So, it follows that plants we grow for their leaves (such as cabbages, kales etc) will benefit from additional feeding with a nitrogen rich food, while plants we grow for their fruits (like tomatoes, cucumbers, squash, pumpkin etc) will benefit from a potassium-rich feed.
As a general principle, we should feed the soil, not the plants.
Soil that has had plenty of organic matter added may not need additional feeding, but generally speaking I always feed plants during the season as well, at least once, to give them a boost.
When it comes to deciding what to use as a feed, you have two choices – you can buy chemical feeds or you can obtain something a little more natural, made from sustainable materials.
I always try to do the latter and where possible I will try and make the feeds myself to keep costs down. But I generally also buy in some good quality organic feeds too.
Broadly speaking there are two options – a liquid feed (usually made by diluting a concentrate) or a dry feed (in powder or pellet form).
Pelleted or powder feeds are spread over the soil surface and worked in with a rake, generally at the time of planting or a few weeks before.
Liquid feeds are simply applied with a watering can direct to a plant, and are particularly useful for feeding container plants, which always struggle to find the nutrients they need to grow in their pot. Liquid feeds can also be applied as a foliar feed – that is sprayed on to the leaves – as a quick tonic.
Making your own liquid feeds is an inexpensive way to use easily available sustainable materials and get a top-quality feed for your vegetables at the same time.
Generally speaking I make two feeds each year in buckets or bins in the garden, keeping them covered and as far away from the house as possible, as they can get a bit stinky.
The first one is nettle tea, which is high in nitrogen and therefore a great boost for plant leaves. Simply chop fresh nettle stems and pack them in to a bucket, covering with water.
Cover with a stone or slab to keep the nettles submerged in the water.
Leave it for two-three weeks. The resulting feed will smell foul, but is dynamite for plants as it's full of nutrients. To use, dilute 10 parts water to one part nettle feed.
Fruiting crops like tomatoes will benefit more from a potassium rich feed like that made from comfrey.
The process (and dilution rate) is the same to make comfrey tea.
I should add finally, that though it might seem a little uncouth, human urine is also an excellent, freely available and abundant high-nitrogen plant feed! It too should be diluted (10-one) before being applied to the roots of plants.
* Michael Kelly is author of 'Trading Paces' and 'Tales from the Home Farm', and founder of GIY