Mulch Mulch Mulch

Mulch: What is it?

Any takers? I thought that I’d better clarify a few things about mulches and why we mulch so that everyone in the garden is on the same page.

Mulch is a protective ground cover that is placed on top of soil. Its primary uses are conserving soil moisture and preventing erosion. Because the soil is covered with an additional organic layer water doesn’t evaporate as readily and soil is not exposed to winds which might whip it away.

In addition to these qualities mulch can also provide nutrients to the soil. As the mulch material is broken down by soil microbes this releases trace nutrients that may be contained in the mulch material. Often times the factor limiting mulch breakdown (as in compost) is Nitrogen availability so it can be useful to place Nitrogen rich material beneath your mulch layer if you aim to feed the soil.

An additional benefit to mulching is it is useful in suppressing the growth of weeds and weed seeds. By covering the soil and preventing light through mulch can block the access of weeds to light. By mulching thickly around the plants that you want this keeps volunteer plants at bay. Our tactic when we first revitalised the food forest was to sheet mulch the cooch grass. When sheet mulching the idea is to make an impenetrable layer that is so thick that light doesn’t make it through and the plants you covered die off. You can use anything organic that comes in a sheet, such as newspaper or cardboard. Easier said than done when dealing with cooch. To ensure that the grass doesn’t run it is important to place the sheets at least 6 layers thick and to have overlaps of  15cm when placing the sheets down. With species such as cooch I’ve been told to give up on Newspaper and just go for sheets of cardboard with a 15cm overlap. From what I saw when the cooch came back in spring, I’m inclined to give up on paper. Another good idea when embarking on sheet-mulching is to mow or cut the unwanted plants as much as possible and to add manure to bring the Nitrogen ratio up. This will assist in decomposing the mulch and generating an environment unsuited to plant growth.

Different kinds of mulch have different benefits. A thick, coarse mulch like bark chip is good for an area like the food forest as we want the mulch to stay around for as long as possible. Woody mulch is mainly broken down by fungi so this process is slower than bacterial breakdown that happens quickly for non-woody material. For an area like the swale bed it is better to use old straw or leaf litter as this is not as thick and breaks down faster. However, mulch must still allow the soil to breathe. Grass clippings and similar materials are no good for mulching as they all press together and rot without air which stinks and is no good for the plants. Leaf and grass mulch is usually chopped up before use to allow air spaces in the mulch. Hence, the advent of the mulcher.

One aspect of mulches that shouldn’t be forgotten is that of “Living Mulch”. When we have a living ground cover this provides the benefits of a mulch. Ground cover plants keep the soil cooler and alive and often generate benefits for other plants in the soil. I’m not a huge fan of Ivy but it grows in my backyard as a living mulch underneath a pine tree that nothing else seems to live under.

So whats the drawback? Well mulch made from some eucalyptus bark and leaves is “Aleopathic” this means that it inhibits other plants from growing. This is why we don’t use the bark mulch on the veggie beds. If you know what trees your mulch is coming from then this isn’t so much of a problem but its very hard to get specific mulch from supply companies.

Another drawback of mulches is that they don’t have the same thermal mass as the soil. This is why we want the mulch in the summer so the soil doesn’t heat up. However, in the winter the presence of mulch keeps the soil cooler and may lead to frost damage. As a rule I remove mulch from the soil surrounding trees in the winter and don’t replace it until a ways through spring. Speaking of which, as good as mulch is, it is never a good idea to have it right up against tree trunks. The decomposing of mulch is rife with microbes and fungus and these are not friends of a tree’s trunk. If mulch is right up against the trunk it can let invaders into the tree trunk. This is especially a worry with many fruit and nut trees which are grafted. The graft point is a weakness in the plants immune system and mulch against this part of the plant is practically begging for infection.

So thats all the who, where and why of mulch that I can think of at the moment. Any questions, I’d love to answer them.

Posted in Uncategorized | Leave a comment

Community Day in the Garden

Hi everyone, just a reminder that this Saturday is our Community day in the garden. We will be open from 10am and will have a range of activities underway including cobbing the chook house, planting, sheet mulching workshops and garden decoration.

We will also have some seedlings for sale out of the garden if you’d like to stock your home garden with winter vegetables.

We’ll have the barbecue going and everyone is encouraged to bring a plate of nibbles to share. Send me an email if you’d like to be catered for.

The garden is on Loftus st in Yarralumla just down from the shops. See you guys on Saturday.


Posted in Uncategorized | Tagged , , | Leave a comment

Deep Bedding Systems for Animals

I love our school chickens, they are incredibly social birds as they grew up with the yr 3/4 kids last year and are always bright and chirpy when I arrive in the garden. We are currently undertaking to upgrade their quarters. We aim to add more Cob to the coop, extend their roof space, get a gutter to catch water from their roof and have roofed the coop to keep out the cockatoos and pidgins that were pinching all their seed.

The second and most major improvement we will make to the coop will be to set it up to run a deep bedding system. Deep bedding systems let the animal bedding pile up so that it builds the mass to allow it to begin to compost in the coop.

Chickens produce very hot manure because it is a mix of both manure and urine. This means that the Carbon : Nitrogen ratio is very low as . For optimal composting you want about 25 – 30:1. ~Thirty parts carbon to one part nitrogen. If the Carbon : Nitrogen ratio is very high (excess carbon) there is not enough protein for the micro-oganisms to function and decomposition slows down. If the Carbon : Nitrogen ratio is low, then there is an excess of nitrogen and the microbes do not get enough carbohydrate and things really start to stink.

This ratio does not mean that when you have a kilo of kitchen scraps that you need 30 kilos of hay. Rather the mix that most people come two is two parts green matter to one part brown. For our purposes it means that if the chickens coop becomes smelly it needs some more carbon to act as a sponge and soak up the excess nitrogen. If we get this right we can keep adding to the bedding that is in the chicken run and when we pull it out it will be part way towards soil.

Composting done right doesn’t smell and the chickens allow us a great way to covert scraps to soil. Hopefully we can get the deep bedding system set up soon by building a small brick wall around the edge of the chicken coop which will let the bedding pile up.

Happy gardens


Posted in Uncategorized | Leave a comment

Scenes of Summer

Hi everyone, sorry for the elapsed postings, time got away from me with all the stuff to do for summer. Swimming, eatting, playing music and catching up with old friends.

I wasn’t working in the school garden in summer, it looked like we were going to run out of resources in the garden so school parents assumed control of the wheel so I could work in Term 1. However, we have received additional assistance to continue the garden for 2011. So I’ll keep you all abreast of the developments as they eventuate. In the meantime, here are some photos of our garden following the summer rains and sunshine.


Posted in Uncategorized | Leave a comment

What is a Weed?

One thing that I have learned running the school garden is that people love to weed. I guess that everyone knows how to pull plants out of the ground and its kind of fun and alot of people have spent alot of time battling weeds in their garden.

However, quite often what we think of as weeds are beneficial to the garden and to other plants in the garden. Many species that grow appear in the garden because the soil is too compacted or lacking in a nutrient. “Weeds” like dandelions grow with a long tap root and these long, strong roots act to break up and add air to soil that have become compacted. Often these plants also mine nutrients from the soil and make them available for other plants. Once the soil has been repaired, other plants will out grow the weeds because the condition that caused the weeds to grow has been fixed.

An example of this in our school garden is a plant called “Cape Daisy”

Cape Daisy in Bloom

This plant is in the Daisy family (Asteraceae) and kids used to pick it to make daisy chains when I went to school. It grows all over Canberra and its yellow flowers are attractive and it attracts pollinators like bees which then pollinate our fruit trees. In addition its leaves concentrate nitrates and other trace minerals so it is a great plant to compost. However, it can be good to remove if you want to make space for strawberries etc.

However, if we are going to remove Cape Daisy it is important to leave the roots in the ground. The plant is an annual so it is unlikly to grow back. Also, leaving the cut roots in the ground captures the carbon in the soil and allows other plants and soil microbes to utilise the resource. Lastly, the roots of these plants have acted to bind the soil that we moved with the bobcat to build the swale so if we pull out the roots we are undoing this valuable work the plants have done for us. If we don’t bind the swale it is possible it will wash away rather than acting as a sponge.

Plantain (Plantago lanceolata)

Plantain in flower

Plantain is a miracle plant that has gotten a bad rap. Its common name used to be Bandage plant and it has a long tradition of use in European herbalism. This plant makes natural asprin and also a chemical which increases rates of cell healing. One leaf can be chopped up and made as a tea and sweetened with honey. I have used this to beat colds, headaches and fevers. There’s plenty of info on the web if you don’t take my word for it.

The ability of this plant to increase cell healing make it useful for dressing cuts. I have heard a few stories of this plant being used on cuts when one was out in the field or without first aid and it acts to stop the bleeding quicker and heal the cut faster. Wash leaves first to avoid infection.

Shepard’s Purse (Capsella bursa-pastoris)

This plant pops up all over the school garden and has big umbrels of white flowers. This style of flower is similar to that of carrots and is great in the garden for attracting pollinators for the fruit trees and beans. It also has edible leaves which are used in Japan for making stir-frys. Its oil is used in the cosmetics industry for skin care.

Well, thats all I have time for now. Happy Gardening. Let all plants help you out and put your effort into a productive activity.



Posted in Uncategorized | Leave a comment

Shots of Spring

The garden has been blossoming and blooming with the warm weather and extra rain. I’ve taken some shots to compare with the photos from winter. I hope you enjoy them.

Posted in Uncategorized | Leave a comment

Worm Farm in a Fridge

The fridge ripe for farming

When I was offered the chance to come up with a design for a school garden I wanted to include a wormfarm. Kids love worms and a worm farm is a great way for them to see worms in action. Additionally, the worm-farm turns food scraps into rich compost and generates a liquid that can be used as fertiliser. Worm castings can be used as seed raising mix and worm juice can be used in the place of seasol when soaking seeds, transplanting or adding pep.

I had seen designs for wormfarms in a few books i owned. They needed to be dark, have a place to collect juice and castings and keep the worms cool in summer and warm in winter. Many people use old bathtubs which already have a plug for drainage but I wanted something with a lid.

Fridge lid with thermometer

An old fridge is ideal for a wormfarm because it is insulated and helps to keep the worms at the right temperature. They are cheap and a waste problem so seemed ideal. I bought a degassed fridge at the tip for $20 and removed all the shelves, motor, coil, screws and the fridge seal. The worms need to breathe.

I used the holes in the back of the fridge as a worm juice drainage point and fitted a bulkhead from the hardwear store so I could attach a hose to it to drain the juice into a bottle.

Brick in the fridge to reduce the area and assist drainage

I placed bricks and gravel to help drain the farm in the bottom of the fridge. This also reduced the depth of the food scraps. If the scraps are deeper than 60cm they can decompose thermally and stink. I then proceeded to add shreaded newspaper to the farm.

Shredded paper for Carbon in the fridge

Carbon acts like a sponge when composting. All the nutrients and other elements and minerals in your food gets broken down by the worms eating it and then binds to carbon in the farm. This results in rich humus being generated by the farm.

Paper and food scraps composted by the worms

Once we had placed a thick amount of newspaper we wet it slightly and added food scraps. The smaller the food scraps are the faster the worms can eat. I mounted an old mincer to add to the fridge to help the kids get into active composting. You don’t need to add water to the farm once it is working. The water the worms require will be added as the food scraps and too much water will make the farm anaerobic (no air) which is when smelly rot will occur.

I haven’t added vents for harvesting casting becuase the farm opens from the top. To harvest castings you push all the casting to one side and fill the other side with more ripped paper and food scraps. Once the worms eat all the food in the first pile they will migrate to the second pile. The first half can be harvested for use sowing seeds or fertilizing plants.

Worm castings and paper on one side of the farm

The worm farm is a crucial addition to a home garden. They are great as they can be made almost anysize and easily fit in the laundry. They require no turning like a conventional compost pile and dont smell if done correctly. Search on the internet for more ideas if your interested or ask me questions in the comments section.

Open worm farm sitting in the sun

Posted in Uncategorized | 1 Comment