Month: September 2006

In March, I made a post about the weed burner I use in my garden.

The main reason for writing on this again is because I notice a lot of people find this blog by searching the Internet for weed burners. It seems like there is really not very much information about weed burners available, and this blog is one of the few places that has anything. Anyway, since another summer growing season is quickly coming to an end, I thought I would share some more experiences with it.

I hope some of you reading this that are just passing visitors will come back and share your comments and experiences on this or other posts.

What it doesn’t do

I can’t emphasize enough what came out in the comment discussion on the previous post. The marketing that goes along with these products is frequently misleading. It does not kill established weeds, it just burns the tops off, which then grow back. It certainly does not kill grass. It does not kill weeds in between bricks or stones. Unless you have a very powerful one, it will be very slow going and not useful for snow and ice. Does this pretty much cover the marketing side of things?

What about using it together with a tiller to kill weeds?

If you are one of those people that thinks a garden tiller will kill established weeds or grass, you are mistaken, it doesn’t and never will. Using a weed burner together with a tiller will not work any better.

If the ground is free or mostly free of established weeds, and you use a tiller to loosen or mix the soil, it can be useful to use a weed burner at the same time.

Before you use the tiller, if you think the ground may be contaminated with weed seeds, burning the ground first can help prevent turning them under. If you are turning under something like compost, and you think it might be contaminated with weed seeds, it too can be burned. Soil amendments are best spread out in a thin layer before burning them.

After you have used a tiller, it’s common to turn up seeds that have been lying dormant in the ground, which can also be killed with the weed burner. If you have turned up a few established weeds in the course of tilling, burning the roots of these weeds may in a few cases prevent these weeds from re-establishing themselves, but I wouldn’t really count on this working very well.

When is it most useful?

The weed burner really works best against weeds right after the seeds germinate, and send little vulnerable green shoots up. Just a quick pass with the flame will quickly kill these with much less effort than using a hoe or cultivator. In the spring, when the weeds first start to emerge, you can kill 80-90% of weeds by simply making a pass with the weed burner every few days. Of course once you start sowing seeds or planting seedlings, the weed burner can’t be used anymore. A longer term solution is to use another weed control method like mulch.

Once your crops are established, you may again be able to use the burner in between the rows. This year I found it particularly useful with my garlic crop, as garlic is a very hardy plant that can tolerate a good bit of singeing. There are certainly many plants that cannot tolerate being burned, even when established, so be sure to test it on a few plants first before risking it on your entire crop.

What are things to look for when purchasing one?

Bigger is better. Without a doubt, you will probably be happiest with the largest one you can find. It can be tedious covering large areas with one that is too small. Since you are attacking weed seeds, having a flame that is hot enough to penetrate a few more millimeters of dirt is a real advantage. As far as the size goes, little else matters other than the BTU rating.

Beware however that the larger a burner you get, the larger a tank of propane you will need to buy to go with it. This is because as propane expands it gets cold and freezes. If you try to use too small of a propane cylinder with too large of a burner, the propane tank will freeze up, and you will have to wait several hours before you can continue. It is always an option to buy a bigger burner, but use it turned down.

It is not necessary that the burner you buy is called a weed burner. Any hand held propane burner will work, as long as the BTU rating is appropriate. Make sure the handle is long enough, so you don’t have to bend over when using it. You can save quite a bit of money by buying a simple burner, rather than a ‘weed burner’.

It can be useful to have the lighter built into the burner, so you don’t have to carry a separate lighter around with you.

Make sure the shape of the flame goes along with what you will use it for most. If you will cover wide areas, a wider flame is better. If you will use it around plants, a point shape is better.

What are the disadvantages?

It is not a silver bullet for weeds! There are many cases where it just can’t be used, or doesn’t work very well.

If the ground is wet, it takes more time to heat it, and therefore things go a lot more slowly.

You can’t use it in dry conditions, because it is a fire hazard. You have to be careful when using it around mulch, because it is usually flammable.

Propane burners are not very ergonomic, and some people may find they start developing RSI related problems.

Just like when you use chemicals in your garden, the weed burner will kill beneficial insects and other organisms.

Weeds can develop resistance to weed burners like they can to chemicals. I have already started to notice this a bit in my garden. Also, since it works better against some weeds than others, you may have a problem with weeds more tolerant to being burned becoming more established in your garden.

It’s not a toy, and can be a hazard in gardens with pets or children.

You need to have a pretty large garden for it to be a cost effective and useful investment.

If you grow any plants that are a member of legume family there is a very important bacteria needed in the ground you may not be aware of.

Leguminous nitrogen-fixing plants as they are called include all green and dry beans, lima beans, garbanzo beans, soy beans, fava beans, peas, field peas, clover, alfalfa, vetch, peanuts, lentils and probably others.

These plants are unique in their ability to absorb nitrogen from the air and fix it into the ground. This means these plants are normally able to provide most of their own fertilizer, and so can often be grown in very poor soil with little or no added nutrients. In fact these plants will usually leave the soil richer than before they were planted. In between growing other crops, farmers and gardeners often plant ‘cover crops’ that are intended to fix nitrogen into the ground and otherwise improve it.

These plants depend on the presence of a rhizobia bacteria in the ground. This bacteria does not normally occur naturally in the ground, and many gardeners will have to establish it themselves. Gardeners are often unaware they need to do this. Once it is established, it normally persists for a very long time and so is no longer an issue.

There are four different strains of rhizobia bacteria, and you must have the proper strain for the particular crop you are trying to grow. There is one strain for soy beans, one strain for garbanzo beans, one strain for clover and alfalfa and one last strain for most other plants. If you establish one strain of bacteria then grow something that requires a different strain, you will need to establish that strain separately.

If this bacteria is not present in the ground you can expect very poor crop performance.

Sometimes packages of seeds are labelled with a warning about this bacteria, but few warnings go so far as to tell you you will probably have a partial or total crop failure if you lack this bacteria. It is very important to establish this bacteria in your ground if you are growing these crops!

There are several ways to establish this bacteria. If you have been growing these crops already for a number of years, you probably already have it. If you or a neighbor have some land where this bacteria is already established, a few shovelfuls of dirt are often all that is required to establish it in a new spot. The bacteria will also usually establish itself, so you may be able to just wait through a year or more of poor harvests until it is finally in the soil. Finally you can establish this bacteria by using an inoculant (see below).

A common technique to firmly establish the bacteria in a particular spot is to make two successive plantings of the same sort of plant, even if you have to temporarily set aside good crop rotation practices.

Finding a supplier for inoculant can be difficult. In the UK there is a single manufacturer, Legume Technology Ltd. People living in the US can often simply find it at a garden center, but it is usually only the strain of the bacteria used for garden peas and beans. If you want other strains, or you want to order it by mail, Bountiful Gardens is a good source. Bountiful Gardens will also ship overseas, so they are a good source for people living outside of the US as well.