16 August 2002

Catch weeds early if maize is organic…

TIMING is all-important when controlling weeds in organic maize and the first pass with a comb harrow must be carried out before weeds can be seen with the naked eye.

Reporting the experiences of maize growing trials at Gordon and Linda Tweddles organic unit in Co Durham, MGA agronomist Simon Draper says white seedlings can be seen germinating under the soil soon after drilling. "These must be killed off, if you are to be in with a chance of controlling the weed population.

"That really requires dry weather, but it is so important it needs to be done in less than ideal conditions if necessary. Ideally, the comb harrow should be brought out every week for four weeks, starting three or four days after sowing."

It has been necessary to continue comb harrowing up to the 8-leaf stage and Mr Draper assures growers that this is possible, without harming maize plants. After that, he recommends using an inter-row hoe to throw soil into the maize, burying any remaining weeds.

Trials at the Co Durham site also tested later sowing to try and reduce crow and rook damage. But these were not successful, he says. "We sowed half the crop in late April and the rest 4-20 days later. The idea was that the later-sown crop would go into warmer soil and quickly reach the 3-4 leaf stage, where it would be relatively safe from birds, but it hasnt worked."

Full results are available from MGA (0118-976 1276, fax 0118-976 1451). &#42