Fertilising 101

Part one of what may be, in the unlikely event that I have time, a series on Sharehouse Herb & Veggie Garden Basics.

I am handing over 'my' garden (more correctly, the garden that I planted) into the care of the people who will still be living here with it and hopefully enjoying it. In the interests of a properly documented hand-over, I am making some notes about how to look after it. I am not an expert, by any means, but then, with gardening, few people are. All you can do is read around, wonder at all the contradicting advice, attempt to translate the more arcane terminology, throw your hands up in disgust at it all and just settle on a method that works for you.

So: The Basics Of Fertilisers.

Fertilisers should generally be applied after rain or watering. If you're building a new veggie garden or planting new crops, you will add some food then as well into the soil in the form of a good layer of compost, plus other stuff (Google the plant you're growing for info on what to feed it at planting time). Once it's growing, the fertilisers for herb & veggie gardens come in three rough categories: nitrogen-heavy, potassium-heavy & general feeders & tonics. There is lots of stuff you can read up on that will tell you to use XX-YY-ZZ fertilisers for particular purposes, but I have never been able to adequately decipher it. What I have puzzled out is:

Nitrogen Is For Leaves
Nitrogen-heavy fertilisers are for feeding lush, green growth, where you want lots of leaves to grow really quickly & not accumulate too much flavour. Lettuce, kale, silverbeet, rocket, broccoli, Asian greens, mustards and so on: when the point of the plant is the leaves, and you want lots of lush, fast growth of them. The fertiliser I use for this is Charlie Carp, which is made of ground-up corpses of pest carp in Australian rivers. I start feeding as soon as the 'true leaves' have appeared on the seedlings, and continue to feed twice a week for as long as the plants are growing (until they 'bolt', or send out a flower stalk, which is pretty much over-red-rover for leafy plants- unless you're talking about broccoli in which case the flower stalk is the bit that you eat). I mix a generous lidful of Charlie Carp & along with a lidful of Seasol or cupful of worm-juice (they are both general feeders, see below) into a big watering can & fill the rest up with water.

NOTE ON HERBS: Even though you eat them for their leaves, not all herbs like lots of nitrogen fertilisers! Actually, 'dry' herbs like sage, thyme & rosemary don't want any at all- they grow slowly, without much food, which causes their leaves to be more strongly flavoured. These guys should get only an occasional (every 2 weeks in spring/summer) inclusion on a 'general feeding' round. Basil, on the other hand, likes nitrogen fertilisers & should be fed whenever you're feeding the leafy greens.

Potassium Is For Flowers
If the plant you're growing produces fruits for you to eat, then it needs to flower. To encourage flowering, you feed potassium, usually in the form of 'sulphate of potash' (you can get it from Mitre 10 or K-Mart). This is eggplants, capsicums, chillies & tomatoes primarily- also strawberries (lots of other vegetables flower to produce fruit, but for instance beans are pretty self-sufficient & don't seem to like lots of fertilising, they will flower without it, and things like zucchinis & cucumbers like 'general' foods, they do not seem to be fussed on potassium). So OK you want to feed your eggplants, tomatoes, chillies & strawberries plenty of potassium, which I do by mixing a teaspoonful of sulphate of potash into a watering can with a some general feeder like Seasol or worm wee, and also a SMALL amount of nitrogen fertiliser- maybe half a cap (yes, these plants need nitrogen as well, just not too much of it or you'll get loads of lush leaves on plants that refuse to flower). They get the potassium feed once a week in spring/summer, and a general feed once a week.

General Foods Are For Everyone!
There are lots of good 'general' foods, which are not too high or heavy in any of the nutrients but provide a good spectrum of minerals & things. It's probably a good idea to use a range of different things for this purpose so your plants get a varied diet. My mainstays are Seasol & worm wee but people make nice weed teas for this purpose too. So into a watering can I'd dump about a cup of worm wee & a lidful of Seasol, then fill it up with water, and feed EVERYONE with this- herbs, leafy veggies, beans, zucchinis, radishes, tomatoes, fruit trees, potted plants, potatoes- everyone gets a bit of this. Although, some more frequently than others: veggies that grow really quickly for one summer need more food than slow-growing herbs, so for instance most of the veggies get fed twice a week while the herbs get fed about once a fortnight.

Compost of course is the primary #1 general feeder, a balanced diet that pretty much all your plants will like. Compost out of the compost bin or the worm farm is an excellent thing to chuck in when you're building your beds or planting up your pots, and you can also side-dress once the plants are in by scraping the mulch back and putting scoops of compost around them.