When it comes to issues of weed control it seems that every man and his dog has an opinion on how they should be treated. Organic gardeners will have nothing to do with chemical products and many novice home gardeners can't be bothered searching out alternatives.

While big chemical companies keep producing weed killers (and marketing them as organic) most home gardeners will pay the money because they work. They usually take very little effort to apply and work almost immediately. However, the residues that are left in the soil or on our fruits and vegetables are forcing us to consider possible substitutes.

The two on offer that most gardeners - although usually from opposite ends of the spectrum - will employ are solarizing soil or using glyphosate.

What does it mean to solarize soil?

Many organic gardeners have been using the concept of solarizing the soil to rid it off unwanted weeds. The idea is that you cover the ground with a large sheet (preferably plastic or geotextile) and allow the sun to warm up the area and eventually kill the weeds. It usually doesn't work on seeds that haven't germinated yet but can do if the weather is hot enough.

The process can take from one week up to a couple depending on the warmth generated under the plastic.

What is Glyphosate?

Glyphosate is a non-selective systemic herbicide that is applied to weeds and drawn into the plant through their leaves and stems. You would pobably better recognise the name 'RoundUp' more than the term glyphosate as this is the brand that it was initially marketed under.

While glyphosate would kill the weeds its effect ended in the plant itself and it becomes neutral when it hits the soil. This is a big advantage for gardeners wanting to use chemicals against their weeds but not damage the environment and leave residues in their garden beds.

Which weed killer is better?

I'm not about to give you an answer to that question because it's highly subjective and most opinions are valid. So, rather than draw a line in the sand let me at least compare the pros and cons of both alternatives.

Solarize your soil

PROS

• Chemical free


• Once you have the plastic or geotextile, it's a very cheap exercise


• Large garden beds can be managed without too much effort


• Possibility of killing some of the weed seeds before they germinate

CONS

• Can only be used on new garden beds or sections of garden that don't have other plants already growing


• Buying the plastic or geotextile to get started is quite expensive


• Storing the plastic can be a headache. It's a bulky material that you will only use once or twice each season so most of the time this material will need to reside somewhere and take up precious space


• Plastics are made from non-renewable energy sources (crude oil). So while you may be killing your weeds organically you're being a hypocrite regarding the materials you need to do achieve this.


• Plastic doesn't last forever and once you start getting a few holes in the sheets they become ineffective and will need replacing.

Use Glyphosate

PROS

• Inexpensive and readily available


• Extremely effective against growing weeds


• Weeds are usually dead within 7-10 days after applying glyphosate


• It won't leave residues in your soil

CONS

• Can be quite expensive if used over large areas


• It can only be used on plants that are growing and not as a pre-emergent weed killer


• Any plant that comes in contact with glyphosate will die. So, if you're spraying around your ornamentals great care needs to be taken that you don't inadvertently spray them with it.


• While residue from this chemical won't build up in the soil it can build up, and remain, on fruits and vegetables that may have come in contact with it


• While not official, there are many links between health problems and using glyphosate. At present, there appears to be some cause for concern for pregnant women but this has not been verified to date

The Conclusion

In my own garden I'm happy to employ both methods of weed control. If I'm starting out with a new bed and I don't want to waste considerable amounts of time or effort I will start off with solarizing the soil. Then, as plants grow and weeds grow between them I'll readily use some glyphosate to eradicate them.

I know a few organic gardeners who don't have a problem using glyphosate and some home gardeners that will also employ solarization. IMO - both methods are warranted.