Friday, February 29, 2008

Is Gardening Sustainable?

A friend of my brother had a tree blow over in the very strong winds Auckland had last week. My brother knowing I need regular delivery's of mulch dropped a load round at my place which I promptly used on paths and in the chicken run. Last year I probably brought on 3 cubic meters of weeds for compost 3 cubic meters of horse manure for compost and growing potatoes and 2 cubic meters of mulch. The latest delivery prompted me to think about the sustainability of what is commonly thought of as gardening.

As my experience and those I know has shown most gardeners have to bring quite a lot of biomass onto their propertys. This biomass can be compost, materials to make compost out of, woodchips, leaves potting mix etc. This constant inflow of organic carbon is necessary to replenish the carbon lost from soil through cultivation and because most of the crops we grow are leafy nitrogen rich plants that do not store much carbon. Another major factor is that we send all our human manure off site, this very rich outflow of nutrients and carbon must be replaced every year. Obviously having to bring carbon onto your site every year to replace that which you use cannot be sustainable right? And if everyone is doing this we are going to need to put aside a lot of land to grow that carbon.

This constant inflow of Organic Matter is just one of the many reasons why home gardens require a constant inflow of resources. To get around this there are several things one can do. John Jeavons a leading proponent of biointensive gardening techniques recommends that half your garden be planted in carbon crops for compost. Similarly I have planted fast growing plants like Abyssinian bananas, reeds and wild ginger which can be used to make compost out of. I have also planted heaps of trees whose prunings will eventually provide carbon.

Overall though intensive home gardening is only sustainable when land is left in low intensity wild or semi wild states. This is permacultures zones four and five, areas which are unmanaged and which provide space to hunt and gather, selectively log certain trees, collect firewood, observe etc. These semi wild areas also help to create rainfall, harbour beneficial insects, retain soil moisture and keep thousands of important an ecological processes working. Without these areas intensive gardening becomes fragile with nutrient loss, pest problems and drought all becoming real threats.

More on resiliency in horticulture here at Jeff Vails site

Monday, February 25, 2008

A week of gardening

So carrying on from last weeks post I have been getting active again in the garden. A friend came over on friday and we re covered the hot house in plastic. The plastic came from a rubbish bin at a plastic factory and all the other parts of the hothouse (frame, timber, benches etc) were all salvaged as well.

I have been walking round the property and have come up with quite a list of projects to do when I run the retrofitting suburbia course in a few weeks. Rain barrels a grey water system, water diversion channels a mini pond and plenty of planting are all in the works. As my insurance claim for my last camera is being processed I will hopefully have a new one son and my motivation to blog will go up as I document these new projects.

I have planted a bed of carrots and started seeds of phacelia, wild carrot, onions, leeks, lettuce and some more silverbeet.

heres some information I put together about wild carrot

Carrot (wild)

Wild carrot also known as queens annes lace is the ancestor of the domesticated carrot, it is edible when young but quickly becomes too woody to eat. It attracts beneficial insects and breaks the soil apart so should be can be encouraged in low maintainence areas of the the garden or orchard.

A teaspoon of crushed seeds can drunk with a glass of water immediately after sex for birth control. Several scientific studies have indicated compounds in the seeds which may be effective in preventing pregnancy.

It bears some resemblance to poisonous hemlock so care should be taken to make a positive identification.

Tuesday, February 19, 2008

Around the Garden

Things are picking up in the garden after summer holidays and various other interruptions. Over summer there were various setbacks which dramatically lowered the harvest.

The tomatoes I planted grew way too quickly and didnt fruit particularly well. This was probably because I gave them too much fresh compost. The fast growing green growth was then susceptible to fungal disease and many then died off. The courgettes suffered a similar fate but I think they may have been stressed by the incredibly dry temperatures.

After finally pulling out the tomatoes and the sunflowers which were completely spent I have been replanting with Autumn crops. Brassicas, carrots, lettuce, bak choi and silverbeet have all been planted and should provide for some decent winter eating. I am finding that my 9 or 10 garden beds take a decent amount of time and effort to prepare an maintain. Hopefully this will be balanced out by a decent yield of food.

Otherwise the main thing I am doing is preparing the garden for my upcoming gardening course, getting everything tidy and making repairs to the hothouse.

Hopefully my posting will become more regular now I am working more outside.

Thursday, February 14, 2008


Sorry for those who have been waiting for updates, I went on holiday and have just got back. Hopefully posting will be more regular from now on.

Here is some composting directions I have written up for my upcoming guide to retrofitting suburbia.

Hot and cold composting

Composting is the speeded up process of turning once living material into humus. It can be an invaluable way of creating high quality organic matter to feed the soil with.

Hot composting carefully mixes green and brown materials to provide an optimum ratio for the growth of bacteria. These bacteria heat the compost pile up to high temperatures and breakdown of materials is very rapid. Hot composting can kill seeds off weed species, to do this the pile must have a good mix of materials and be kept moist but not wet throughout the breakdown.

During the the rapid breakdown a significant amount of carbon is off gassed as carbon dioxide losing some of this crucial resource. Another drawback is that the pile must usually be a cubic meter in size and while materials may be stockpiled getting this much material on a suburban section may be difficult

Cold composting relies on fungi and larger micro organisms like slaters to break down material. Piles are made by piling roughly chopped brown materials and whatever greens are nearby into stacks. These piles can take two or three years to break down depending on how much moisture is available. I believe this slow breakdown can create a higher carbon compost which is better able to feed the soil than nitrogen rich hot compost.

A cool area beneath trees is a good place for composting, the trees roots are able to soak up nitrogen and minerals which leak from the pile.

Organic materials can also be layered around growing plants for example branches can be chopped and scattered round trees. Weeds can be pulled out and lain down as a mulch across the soil. This allows nutrients to be taken up directly by plants and encourages soil microlife.

Directions for Hot Compost

Gather pile of green and brown materials, should be 50% of each by weight

15cm layer of springy materials, branches, twigs (helps with aeration

Alternating layers of 15cm of green material and 15cm brown material.

Water each layer with 20L of water depending on how wet materials is

Turn pile biweekly, this increases aeration and speeds decomposition. It is however backbreaking and I almost never do it.


Grass clippings (should be in thin layer)
Animal manures (avoid manure from carnivores eg cats)
Kitchen wastes
Coffee grounds


Branches (should be chopped to 5cm lengths)
Twigs (should be roughly broken)
Dried weeds
Weeds which have flowered or become woody
Woody plants such as corn or sunflower stalks
Untreated sawdust
Paper and cardboard (finely shredded)

Compost activators

These kick the process off and speed the composting process

Poultry Manure (organic backyard hens only)
Soil (small amounts sprinkled throughout pile)
Compost (Small amounts added throughout process)

Worm farming
Worm farming is probably the easiest way of dealing with kitchen waste. Tiger worms are kept in a large container and food scraps are added periodically. Liquid from the bin is captured and used as a rich liquid feed in the garden or food forest.

Worms need to be kept in a dark moist environment. To start a worm farm take an ice-cream container of worms and castings from an existing farm and place them in your farm and add some food. To harvest castings take the top layer of food and worms off and scoop out the rich black castings.

Bins can be bought or made out of almost anything, I use a bathtub with a bucket under the drainage hole but use your imagination. Other ideas include large buckets, polystyrene trays or wooden boxes.

Dealing with Tough weeds

Weeds like wandering dew (loved by chickens) and oxalis (a good ground cover) don’t often get destroyed through the composting process. For these weeds I have several large barrels which I throw the weeds into, once the barrels are almost full of weeds I fill them with water screw the lid on and leave them to break down for a year or two. The liquid is then used to feed my veggies and the solids are added to a compost pile.

Putting the barrels in a cool dark corner means the breakdown is slow and doesn’t smell too bad.

Compost teas/Liquid feeds

Compost teas and simple liquid feeds are relatively easy to make and act to boost populations of microbial populations in the soil.

Keeping the tea aerobic through frequent stirring is important to preventing negative bacteria from building up. Do not spray the tea or feed onto salad crops or fruits or vegetation which will be harvested soon as not all bacteria will be befenicial.

If using tap water leave it in a bucket for a day outside, this will allow some of the chlorine in the water to evaporate. Rain water would be more ideal.

There are heaps of variations out there the two recipes here are just examples J

Compost tea recipe.

Suspend 1 – 2kgs of well made compost in panty hose in a container of 10 – 20 liters of water.
Add a handful of seaweed powder or rock dust if available.
Add a handful of seaweed powder or rock dust if available.
Stir frequently for 4 – 5 days.
Strain the mix through cheesecloth or a fine screen
Spray onto plants and soil.

Nettle Liquid feed recipe

Pack a bucket with nettle leaves
Fill the bucket with water
Leave for one – two weeks stirring occasionally
Strain the mixture and dilute ten to one
Spray onto plants and soil