Category Archives: Gardening

Are There Toxins in Your Compost?

Well, this is a bit scary when you consider the compost is going into organic gardens…

As thousands of cities have begun composting yard waste and hundreds more begin collecting food scraps on a large scale, new questions are emerging about what kinds of things make their way into compost and whether any of them pose a threat to humans and the environment. Federal laws do not require compost to be screened for contaminants, of which plastic and glass are only the most visible. Random tests of compost used in organic agriculture have occasionally turned up elevated levels of lead and traces of pesticides. Last month, the US Composting Council, the industry’s trade group, warned its members to watch out for grass clippings laced with Imprelis, a new weed killer from DuPont that does not easily break down in compost piles.

Organic Snail and Slug Pest Control

There are many ways of dealing effectively with garden pest snail and slug problems.

Encourage Natural Predators

Natural predators of snails and slugs are rats, frogs, birds, lizards (especially blue tongue lizards) and, perhaps most importantly – centipedes. Centipedes and Leopard Slugs (those enormous spotty ones) are the most important slug predators so don’t kill them!

Encourage them to stay in your garden by providing suitable habitat, such as rock lined ponds, prickly shrubs, logs, and nesting boxes.

Incorporate Farm Predators

Ducks, notably the Khaki Campbell, can clear a badly infested garden in a few months. However, they should be kept away from young plants that could be trampled by their webbed feet.


As a garden pest, snails are easier to capture than slugs. But timing is crucial. Snails are prolific breeders. So for best success you’ve got to nip snails in the bud before their breeding season gains too much momentum as the weather progresses from dry to moist.

One way is to get the jump on them by sussing out where they are likely to be spending the dry season (e.g. leafy, cool, shaded areas with lots of hiding places such as creeper covered walls and brick stacks) and giving it a massive soaking in late summer – enough to break dormancy by dissolving the seal snail’s form over their shell opening. Then mount an active trapping campaign.

Pop captured snails straight into a bucket of fresh slaked lime (hydralime).

Hand Picking

Any garden pest snail or slug (except for the big spotted Leopard Slugs which actually hunt down other slugs!) that I come across is marked for destruction. However, my favorite time for hunting is on wet dewy mornings.

As an early riser, I have noticed that snails come out in droves after a heavy downpour of rain. They are sitting ducks (it’s not hard to be faster than a snail!) and you can literally collect hundreds each time you do it. My chooks got thoroughly sick of them.

Anyone have any good recipes for escargot? This French delicacy is, after all, based on the common garden snail! I believe the snails need to be purged first by feeding on bran for a short time. Any ideas?


After rain, when conditions are snail friendly, place small mounds of fresh bran sweetened with a little castor sugar around the garden. Venture out a few hours after dark with a flashlight and harvest up the snails. Continue every night for a fortnight.

You could also put a little pile of this lure beside your new seedlings – with a bit of luck the snails will prefer it and leave your poor babies alone!

The little black slugs that are hard to catch by other methods, will find hollowed out grapefruit shells an irresistible lure. You could also give cabbage leaves and carrot skins a go to lure out both slugs and snails.


For easy movement, snails and slugs need a firm stable surface to glide over. Unstable surfaces such as fresh ash, soot, bark chips, gritty sand, fine sawdust, or dry crumbled egg shells tend to stick to their underside and hamper their progress considerably. garden pest snail

Sprinkle a band of fresh ash around your plot of young plants… Though you can’t keep snails and slugs away with these barriers, you can at least slow them down!

A mulch of oak leaves is also reported to be a good deterrent.

If the situation is desperate (and you have an acid soil anyway), you could also try fresh slaked lime. It is caustic and keeps them at bay for several days.

In some areas garden pest snail attacks are so bad that it’s hard to get young fruit trees established. In these cases placing a tire that has been painted inside with a strong copper sulfate solution around the tree is a long lasting deterrent.

Protect Vulnerable Plants

You can also protect vulnerable plants by covering them with clear plastic bottle halves.

Snail and Slug Traps

There are a variety of clever strategies you can use to trap pesky snails and slugs:

Habitat Traps

Snails like small hollows in cool places to hide in when the sun comes out. You can make habitats that attract snails, making it easier to hunt them down. For a short-lasting but irresistible snail palace, I have found a handful of cardboard toilet roll cylinders tied together with a rubber band effective. Put it in a shady, moist, cool place that’s easy to reach. You might also like to try a few bricks placed side by side 3 cm apart under an upturned cardboard box, or short lengths of PVC pipe off-cuts.

Beer Traps

Isn’t it annoying when you find a half finished stubby of beer that has long gone flat? Never fear! You can now put it to great use as slugs and snails love beer and they don’t care if it’s flat either. Just sink a wide jam jar into the ground so its rim is level with the soil surface, and fill it up with stale beer. Adding a little sugar (2 tablespoons to a liter of beer) makes the trap even more effective.

To stop it overflowing with water from rain or the sprinkler make a canopy out of the bottom of a plastic bottle (make sure you cut out some doors for the critters to get in). Garden pest snail and slug hordes will dive in and drown – what a way to go! You can use the trap over and over – just scoop out the dead and top it up now and pest snail

Biological Control

A microscopic nematode worm that preys on slugs is available commercially as sachets from organic gardening suppliers. They are simply watered into the soil and are effective for 6 weeks. garden

Compost – Carbon-to-Nitrogen Ratios

A couple of months ago I posted about Compost-What’s In and What’s Out.

However, it’s not enough that you throw your organics, food and yard waste into your compost bin (although it’s a good start!)  You must also be aware of the carbon to nitrogen ratio so as to keep your compost happy, healthy, and not stinky!  For best performance, the compost pile, or more to the point the composting microorganisms, require the correct proportion of carbon for energy and nitrogen for protein production. Scientists (yes, there are compost scientists) have determined that the fastest way to produce fertile, sweet-smelling compost is to maintain a C:N ratio somewhere around 25 to 30 parts carbon to 1 part nitrogen, or 25-30:1. If the C:N ratio is too high (excess carbon), decomposition slows down. If the C:N ratio is too low (excess nitrogen) you will end up with a stinky pile.

Below are the average C:N ratios for some common organic materials found in the compost bin. For our purposes, the materials containing high amounts of carbon are considered "browns," and materials containing high amounts of nitrogen are considered "greens."

Estimated Carbon-to-Nitrogen Ratios
Browns = High Carbon C:N
Ashes, wood 25:1
Cardboard, shredded 350:1
Corn stalks 75:1
Fruit waste 35:1
Leaves 60:1
Newspaper, shredded 175:1
Peanut shells 35:1
Pine needles 80:1
Sawdust 325:1
Straw 75:1
Wood chips 400:1
Greens = High Nitrogen C:N
Alfalfa 12:1
Clover 23:1
Coffee grounds 20:1
Food waste 20:1
Garden waste 30:1
Grass clippings 20:1
Hay 25:1
Manures 15:1
Seaweed 19:1
Vegetable scraps 25:1
Weeds 30:1

Note: Many ingredients used for composting do not have the ideal ratio of 25-30:1. As a result, most must be mixed to create "the perfect compost recipe." High C:N ratios may be lowered by adding grass clippings or manures. Low C:N ratios may be raised by adding paper, dry leaves or wood chips.  Many home gardeners will put up with a slight odor and keep some excess nitrogen in the pile, just to make sure there is always enough around to keep the pile "cooking!" Learn more about building a hot compost pile here.

Organic Weed Killer Formula


Most organic weed killer formulas are fundamentally acids.

Weak solutions of sulfuric acid, nitric acid, pelargonic acid (from grapes, apples and carrots as found in the commercial weed killer WOW! Plus) or acetic acid (as found in lemon juice and vinegar) are all effective at suitable concentration.

Acids work by lowering pH level on target weeds just enough to kill them.

The acid only persists for a few minutes after contact with herbage or soil, quickly oxidizing.

The residues left behind by these natural weed killers are either harmless or useful to plants as fertilizer.

Sulfuric acid, for example, oxidizes to form sulfates of any mineral element it comes in contact with.

If the element is calcium, for example, the reaction results in gypsum, a useful fertilizer and soil conditioner.

Similarly, nitric acid oxidizes to form nitrates, which are also the natural end result (albeit in higher concentration) of the nitrifying bacteria found in soils.

The Weed Option of Last Resort

Use weed killers only for intractable weed problems. Good husbandry of providing ample water and food to your plants, with a little help from hand tools and manual weeding (or let your chickens or ducks do the work for you while fertilizing at the same time) are still the preferred options for most weed problems.

There are also other weed management methods available.


Vinegar Weed Killer

Acetic acid is a great organic homemade weed killer and can be found in vinegar, as well as lemon juice.

While most vinegar has an acid content of around 5%, a more concentrated solution of 10% to 20% will more effectively kill weeds.

At the right strength this organic weed killer will kill the leaves of any plant it comes in contact with, but not the roots.

Because of this it is most effective on young weeds which don’t have enough energy stored in their roots to make a successful comeback. Repeated applications will be needed to permanently disable more established weeds.

Vinegar Weed Killer Recipe

• 120 mls (4 ounces) Lemon juice concentrate

• 1 liter (1 quart) white or cider vinegar

Simply mix the two ingredients together in a spray bottle and you have your organic weed killer formula.

Spot spray it directly on the weeds, being careful not to spray desirable plants. For the most effective result the best time to spray in during the heat of the day.

Bleach Weed Killer

Bleach has a similar mode of action to the acid-based organic weed killer formulas in that it causes an extreme shift in the pH of the target plant. The main difference is that bleach shifts pH to strongly alkaline (the opposite direction to a shift to strongly acid).

Being a compound of the elements sodium, chloride and oxygen, bleach in the environment soon oxidizes to leave a residue of common salt (sodium chloride).

While salt itself inhibits plant growth, if used sparingly, the salt residues left behind by bleach soon dissipate with rain or irrigation. The treated area should be OK to plant after two days.

Only a weak bleach solution (around 4% of active ingredient) should be used to make this organic weed killer formula. Just pour into a spray bottle as is and spot treat the weeds you want to remove.

Take care to avoid contact with skin or eyes. Store safely away from children. If you accidentally spray yourself or desirable plants, immediately flush them with water.

Minimizing pesticides and fertilizers

Pesticides and fertilizers can cause significant harm to public health and the environment. Most pesticides contain potentially toxic chemicals that can cause negative health effects such as cancer and neurological and reproductive disorders. In addition, pesticides can migrate into lakes and streams when it rains. When fertilizers enter a body of water, they can cause oxygen levels to drop, killing aquatic life and posing risks to other species.

It is possible to have healthy, great-looking plants and grass while minimizing the use of harmful pesticides and fertilizers. Minimizing the use of these chemicals means that you don’t need to purchase them as often, thereby saving money. Consider purchasing organic fertilizers (such as compost) or even composting your own food and landscaping wastes for use as a natural soil amendment.  Remember that you can grow Giant Organic Pumpkins from Compost that are awesome and environmentally friendly.

As a reminder, here’s what does and doesn’t work in your compost pile:

What to Include

  • From the Garden
    • Leaves (chopped – to speed their breakdown)
    • Grass (not wet)
    • Plants & Weeds (without ripe seeds)
    • Old potting soil
    • Soft plant stems
  • From the Kitchen
    • Fruit scraps
    • Vegetable trimmings
    • Egg shells (crushed)
    • Tea bags
    • Coffee grounds with filters
    • Shredded paper

DO NOT include…

    • Meat, fish and bones
    • Plastics
    • Metals
    • Fats and oils
    • Dairy products
    • Pet waste
    • Cheese, meat or other sauces

Integrated Pest Management

Integrated Pest Management is an approach to pest management that helps reduce the use of pesticides. IPM means preventing infestations before they start, and using pesticides only when necessary. There are various IPM approaches that you can adopt to decrease over all reliance on chemical-based pest control. Consider the steps below:

  • Use native plants, trees, and grasses.
  • Fill cracks in walls and pavement.
  • Keep vegetation at least 1 foot away from structures.
  • Clean food-contaminated dishes right away.
  • Clean garbage cans often.
  • Make sure compost bins are properly maintained.

Additional Resources