One definition of a weed is an unwanted plant. Weeds could be tolerated if all they did was to make the plot appear scruffy. Unfortunately this is not the case for the following reasons:
Weeds compete for the light, nutrients and water that ought to be going to the cultivated plants, plus harbour destructive insects and diseases. They will, if given the opportunity crowd out and weaken their more deserving competitors. As with human overcrowding, the consequences are similar; stress and disease.
Weeds have developed to be robust and vigorous plants by natural selection, unlike most cultivated plants that have been altered by human selection in response to our wants and needs.
Having stated why weeds are undesirable, what needs to be done:
Methods of weeding are either physical or chemical, but common sense and care needs to be applied what ever you choose to fight the foe.
Physical weeding.
This covers a broad spectrum of control. Obviously the simplest is to pull out the weed. This is ok assuming the soil friable and moist so the entire plant is dislodged, you might need the use of a digging tool such as a hand fork or table knife for more stubbornly rooted weeds. . All weeds are effectively dealt with by this method.
Mulching is when material is put over the weeds , to excluding light . Without light the weeds weaken then die. This can take time to defeat tuberous perennial weeds, but given patience it will work. The covering can old carpet, newspaper, black polythene sheet or wood chips.
When digging with a Fork or a Spade, pounce on and remove any weed or root you expose, perennial weeds and seeding weeds to the bonfire, annual weeds to the compost heap..
The Dutch hoe, draw hoe and cultivator are used to disturb the soil surface, slicing through weed stems and roots. These are used on dry days to allow the weeds to be dislodged then wither and die from the drying effects of the sun and wind. Annual weeds and seedlings are effectively controlled. Perennial weeds will be weakened, but can also be spread by this method. Using these tools has the added benefit of disturbing the soil and so preventing soil compaction and associated loss of moisture through capillary action from the soil. It also exposes undesirable soil dwelling insects that birds will happily deal with.
Less common is the use of flame guns. A flame passes over the plant leaves, bursting the leaf cells and causing the death of the weed, followed by a further application after the death of the weed to cremate the remains.
Chemical weeding.
Contact weed killer. Photo synthesis is prevented by the scorching effect on the weed leaves. this is effective against seedlings and annual weeds. Weedol is an example, it is very swift acting and efficient.
Systemic weed killers are absorbed into the leaves and by translocation to the root, they are effective against all weeds, and particularly useful against perennial weeds. Spot weeding deep rooted weeds such as bind weed using ready prepared hand spays will eradicate these pernicious types of weeds. Examples are Tumbleweed and Round up.
Other types makes the soil toxic to plants for a short time such as Sodium chlorate for example it is more suited to clearing the garden path or waste land that can be left fallow for 6 months prior to cultivation.
. Another can be hormonal, that stimulates abnormal growth of the weed, then its death. Examples are brushwood killers such as SBK.
All current weed killers are rigorously tested and governed by extensive regulation. Often weed killer types disappear from sale simply because the periodic cost of testing and the level of sales makes them uneconomic to market and is nothing to do with human or environmental hazard as might occasionally be dramatically and inaccurately reported.
Weeds compete for the light, nutrients and water that ought to be going to the cultivated plants, plus harbour destructive insects and diseases. They will, if given the opportunity crowd out and weaken their more deserving competitors. As with human overcrowding, the consequences are similar; stress and disease.
Weeds have developed to be robust and vigorous plants by natural selection, unlike most cultivated plants that have been altered by human selection in response to our wants and needs.
Having stated why weeds are undesirable, what needs to be done:
Methods of weeding are either physical or chemical, but common sense and care needs to be applied what ever you choose to fight the foe.
Physical weeding.
This covers a broad spectrum of control. Obviously the simplest is to pull out the weed. This is ok assuming the soil friable and moist so the entire plant is dislodged, you might need the use of a digging tool such as a hand fork or table knife for more stubbornly rooted weeds. . All weeds are effectively dealt with by this method.
Mulching is when material is put over the weeds , to excluding light . Without light the weeds weaken then die. This can take time to defeat tuberous perennial weeds, but given patience it will work. The covering can old carpet, newspaper, black polythene sheet or wood chips.
When digging with a Fork or a Spade, pounce on and remove any weed or root you expose, perennial weeds and seeding weeds to the bonfire, annual weeds to the compost heap..
The Dutch hoe, draw hoe and cultivator are used to disturb the soil surface, slicing through weed stems and roots. These are used on dry days to allow the weeds to be dislodged then wither and die from the drying effects of the sun and wind. Annual weeds and seedlings are effectively controlled. Perennial weeds will be weakened, but can also be spread by this method. Using these tools has the added benefit of disturbing the soil and so preventing soil compaction and associated loss of moisture through capillary action from the soil. It also exposes undesirable soil dwelling insects that birds will happily deal with.
Less common is the use of flame guns. A flame passes over the plant leaves, bursting the leaf cells and causing the death of the weed, followed by a further application after the death of the weed to cremate the remains.
Chemical weeding.
Contact weed killer. Photo synthesis is prevented by the scorching effect on the weed leaves. this is effective against seedlings and annual weeds. Weedol is an example, it is very swift acting and efficient.
Systemic weed killers are absorbed into the leaves and by translocation to the root, they are effective against all weeds, and particularly useful against perennial weeds. Spot weeding deep rooted weeds such as bind weed using ready prepared hand spays will eradicate these pernicious types of weeds. Examples are Tumbleweed and Round up.
Other types makes the soil toxic to plants for a short time such as Sodium chlorate for example it is more suited to clearing the garden path or waste land that can be left fallow for 6 months prior to cultivation.
. Another can be hormonal, that stimulates abnormal growth of the weed, then its death. Examples are brushwood killers such as SBK.
All current weed killers are rigorously tested and governed by extensive regulation. Often weed killer types disappear from sale simply because the periodic cost of testing and the level of sales makes them uneconomic to market and is nothing to do with human or environmental hazard as might occasionally be dramatically and inaccurately reported.