How to Kill Weeds

Weeds are a lot easier to kill than you may think, like flies and cockroaches.

In just the same way that many things other than insecticides will kill pests, many things other than herbicides will kill weeds.

The reason is not too hard to understand – weeds, and any plant for that matter – are carbohydrates. As well as that, they have vesicles and cells that are dependent upon delicate ionic and pH balances.
If you use glyphosate or other systemic herbicides, it takes the best part of a week for it to start working, which is often perceived as being too long.

So go into your cleaning cupboard and see what you’ve got. Any cleaner is usually alkaline or acidic, and most of them will work. What do you have – Ajax Spray & Wipe with lactic acid? That’ll do. Bam Easy Off with sulphamic acid? Yep. An oven cleaner (caustic or non-caustic)? Sure thing.

Any of these things will do the job. The only difference between these cleaning chemicals and the herbicides is the amount you will need to use – with a herbicide a light misting on the leaves will kill the plant, whereas with a cleaning chemical a more significant dousing will be required.

An excellent option that is now being used in some products (along with a herbicide) is acetic acid (vinegar). Get yourself a 5L garden sprayer, tip in a cheap bottle of vinegar, top it up, and give your weeds a dousing, and the weed will curl up and die in a day or two.

Or if you want to do it quicker, use either an oven cleaner, or hydrochloric acid (1:10 will do it).

Btw, I’m not a great fan of glyphosate (roundup, zero). It’s not strong enough. A far more potent product are the once-a-year weeders

Book Extract #7: Irreversible Stains

There are some stains that you just can’t do anything about.  This is because you have not added something that is causing an unwanted colour or odour, but because you have removed (or damaged) the thing that is producing the colour that you want.

Almost exclusively this is referring to things that have been attacked either by bleach or acid.  If you have spilled bleach onto something that has discoloured it, then unfortunately there is nothing you can do.  The process of bleaching is irreversible.  Bleach (section 6.1) is an extremely strong oxidising agent that will destroy most pigments and dyes (particularly in clothes) and will irreversibly discolour some types of kitchen bench tops (particularly cheaper type synthetic laminexes) and paints.

The bottom line is this – if bleach has caused the problem then nothing will fix it.  Sometimes if you are lucky you can restore the surface by physically removing the first few layers by mechanical abrasion (see stain removing strategies) but generally it will never be what it was.  Another approach that may have some limited success is to attempt to steam out as much as you can.  Place a cotton tee shirt or paper towel over the damaged area, then put your iron on top and blast it with some steam.  With a bit of luck you may remove some of the staining.

The same is true of acids.  The two strongest acids that are encountered by the general public are hydrochloric acid (otherwise known as Muriatic Acid and freely available from hardware stores) and sulphuric acid (battery acid).

Both of these chemicals will vigorously attack anything metallic, and if you spill them on pavers, particularly those of a darker colour, they will discolour them irreversibly.

The take home lesson from this is that bleaches and acids, although they can be useful stain removing chemicals, are very strong chemicals and must be handled appropriately.

Shannon Lush Myths #1

The most difficult part about running this blog is the amount of time that I have to spend correcting the myths that have been placed into the marketplace by Shannon Lush.

I’ve delicately tried to tiptoe around the issue for a while now, but I’ve decided that I can save a lot of time if I simply document the myths as I come across them.

That’s not to say that she doesn’t have some good ideas – she does – but interspersed amongst the good ideas are some very bad ones, and some old wives tales that are just complete nonsense.

Last Monday for example, a bloke called in and said that his clothes smelled after washing. She advised him to switch to cold water, and to substitute 3/4 of his detergent with bicarb soda.

There are several things wrong with this:

1. There is no advantage whatsoever to washing in cold water. Not one. But there are plenty of disadvantages. For a start the fibres are less supple, and less able to release entrapped dirt. Secondly, the surfactants are less active in cold water, and the enzyme activity drops to virtually zero. Also, the laundry bleaches (perborates) are insoluble in cold water.

2. Bicarb is not an adequate substitute for a laundry powder. Laundry powders are very sophisticated formulas with up to 9 different components. Bicarb, on the other hand, has virtually no cleaning properties whatever. (that’s another myth for another day).

So if that bloke is reading this blog, the answer is to use a premium detergent (OMO) in hot water or BioZet in warm water, and hang your clothes out to dry as soon as they’ve finished washing.

Book Extract #6: Why is Dirt Dirty?

Perhaps the most common type of stain is common garden variety (pun intended) dirt.

Exactly what is dirt?  Consider the following scenario, which many of you may be familiar with.  You have just built a new house and you want to put some turf down to create a lawn.  You get in some yellow builders sand, lay it down, level it, then roll your turf on top.

Several months later, after some fertiliser and watering, the turf has bedded in and you have a nice luxuriant lawn.  You decide to add a water feature so you dig up part of the lawn, only to discover that the nice yellow sand has disappeared and its now black, down as far as your shovel has penetrated. In other words, the sand has been replaced by dirt.

What happened?  What’s the black stuff?

Essentially, the black stuff is decayed plant matter called humic and fulvic acids.  Unlike other acids these do not have a well-defined structure, but are large, complex organic structures that contain many functional groups.

Other things in the dirt are mostly inorganic – sand itself is composed of boron and silicon oxides (anything with the word “oxide” in it is inorganic).  On top of this there are calcium and magnesium salts and of course iron oxides (this is the reddish stuff in soils).

A major component of dirt is of course clay. Although mostly composed of aluminium silicates, clay also contains iron, magnesium, sodium, potassium, phosphorus and other inorganic species present mostly as oxides.

Dirt, therefore, can essentially be considered to be inorganic in nature.  Its attachment to clothes is mostly physical.  That is, it may be considered essentially as big lumps of stuff wedged between the fibres.  An important consideration is that dirt contains many oxides.  Oxides in general are very chemically stable, and this essentially makes them resistant to chemical attack.  That is, unlike most stains, you cannot dissolve dirt by changing its chemical form – you need to remove it physically (oxides can of course be dissolved chemically, but the chemicals required to do it would also dissolve your clothes!)

Another major form of inorganic stain is rust, from being in too close proximity to a screw or nail.  This is in a class of its own in terms of stain removal, and it is discussed elsewhere.