[Bluemoon77]

Hello there, I have just got an allotment and looking for a bit of advice.

The allotment hasn't been used for the last 2 years and is overgrown with weeds. 

I am planning to use Glyphosate on it  to blanket kill everything on the plot.  The plot is 110 sq.m and I wondered what amount of glyphosate I need to purchase to cover that size plot.

I have strimmed the weeds down and plan to spray them.

Thanks for any advice.

S

[Trikidiki]

The packaging should tell you the coverage.

Would have been better if you hadn't strimmed the weeds. Glyphosphate needs to be absorbed into growing leaves to be effective.

[New shoot]

Hi Bluemoon and welcome to the forum   

How much you need depends on what you are buying and how you are applying it.  For example, a 1L bottle of Roundup concentrate can do up to 1500 sq. m but you need a decent sprayer to get that.  Applying it via a sprinkle bar on a watering can will go through the mix far faster.

For the size of plot you have, I would say a small bottle of concentrate would be plenty.  I think they start at around 250m mark.  I have a Hozelock hand held sprayer that was around the £12 mark.  It would take a while to do 100 sq. m, but it would be do-able.  A larger sprayer with a lance will set you back about double that. 

If the weeds were tall, strimming was by far the best option.  You don't want to be spraying product up high when you are in there amongst the weeds and it can also cause spray drift, which your plot neighbours won't thank you for.  At this time of year, there should be enough green growth regenerating at the base to absorb the weedkiller.  You may have to spot treat the odd weed here and there, but most will cop for it 

[LILLILEAF]

Hi
I had a big problem with a weedy veg patch this had been left for 15yrs,so they were big and lots of them,i found a weed killer called Rosate 36,the rate of mix was 200ml to 10 litres of water,the price i paid was around £30 for a 5 litre can.
 I say the area is about 20 sq/mtr,i srayed with a knapsack spryer,which is a 20 litre size i paid  £20 for that.
i did the area twice  february 2015,then this spring there was only a handful that came back.So a great result.
 The knapsack sprayer is used many times during the summer as i have other bad places where i live that need more work.
 Rosate 36  you can buy it from A1Lawn,it has been the best weedkiller i have ever bought and a great price to

[Salmo]

You could have sprayed without strimming if there was plenty of green leaf showing. Strimming is probably the best thing to do. You should have raked everything off so that nothing is shielded by debris.

Green leaf is needed to absorb the glyphosate so wait a while until the weeds have grown a bit. Some weeds, especially couch grass, will remain dormant and you may need to spray again in the Spring when any you have missed will regrow. You could cultivate the ground to stimulate regrowth but I would try initially with what comes naturally.

Rosate 36 is a brand name for glyphosate weedkiller, as is Roundup. All effective. Which is cheapest depends on the concentration. The bottle of Roundup I have in front of me says it contains 96g per litre of glyphosate and 1 litre will cover 400sq m (500 sq yards)

I am a great fan of dribble bars. They do not use any more glyphosate if you calibrate them properly. You should also calibrate your sprayer or watering can.

Mark out a 1yd X 25yd strip on your plot with strings, canes or whatever is handy.

Fill your can with a gallon of water (with rose or dribble bar attached). According to the bottle 1 gallon of mix should cover 20 sq metres. Practice appyling the gallon so that by increasing or slowing your walking speed you can apply a gallon per 20 sq yds every time. You may opt to go over it twice if you have long legs or the rose/ dribble bar is slow.

You can calibrate you application with a sprayer in a similar fashion. Probably the big mistake with sprayers is to cover too much ground and not apply enough chemical.

Follow the instructions on the bottle.
Apply when in active growth.
Choose a dry day when there will be 6 hours of dry weather after application.
Leave undisturbed for 2 weeks.

[AnneB]

 Rosate 36  you can buy it from A1Lawn,it has been the best weedkiller i have ever bought and a great price to

Rosate 36 is glyphosate, just packaged in large quantities and in extra strength intended for professional gardeners and farmers.

[Christine]

At this time of the year with growth beginning to slow, why spray? You will need to dig over during the winter so a spade or fork would be a cheaper alternative and do two things at once - remove the weeds and dig the plot.

[Nobbie]

As you've strimmed the weeds, probably best to leave for a couple of weeks for a bit of re growth so that there is more leaf area to absorb the glyphosate.

[Yorkie]

As AnneB says, Roseate is for professional use only.  It requires a licence to use and this forum cannot condone its use or anyone suggesting its use.

Focus on products sold in garden centres for the amateur gardener.

[BabbyAnn]

At this time of the year with growth beginning to slow, why spray? You will need to dig over during the winter so a spade or fork would be a cheaper alternative and do two things at once - remove the weeds and dig the plot.

bear in mind that winter in Scotland might be a bit more challenging than further south so could take longer.

But I'm inclined to agree that if you could avoid weedkiller and get stuck in a bit at a time, you are already digging the plot over at the same time as you weed.  A lot depends on the soil type - if it is heavy clay, it can be difficult to clear reasonably well and is a lot more hard work.  And the type of weed too - sometimes it is worth having the plot a year or two to get a feel of the problems before resorting to alternate measures if you find your usual method isn't working so well.  If you find the weeds are still growing faster than you can dig them out, you can weight down a dark cover such as black plastic or weed suppressant over the soil surface to prevent them from coming up while you carry on clearing the rest of the plot.

Whether you use weedkiller or use manual labour, where ground has been cleared, improved light levels will encourage dormant weed seeds brought to the surface to germinate quickly so you never totally eradicate them all.

[Growster...]

Like a certain beer, Glyphosate reaches the parts other ways of gardening cannot reach, but the real problem is that if you have couch grass and other nasties, you'll need to dig it all out anyway, so you might just as well knock down the foliage, by all means spray once, but then decide to start to dig a square yard at at a time...

Try thinking about using a mattock or an Azada (even a Growstada..;0) to just scrape off the top inch or so, chuck it to one side in a separate heap, then dig, delve and collect the old stems and roots and get rid of them for good. But just do one yard at a time. That's important.

Sorry it's going to be a bit hard, but within a year, you'll easily notice the difference, (pop a few spuds in next Spring; you'll churn up the soil magically as you earth them up, and then dig the little beauties up for the perfect Sunday lunch), and it two-plus years, you'll motor ahead!

I use Glyphosate to make my small beds easier to grow from. I can mow the paths in between, and not worry about the plants or the grass, because there is a small barren area between the two.

It works for me as an ageing Growster anyway..;0)

[Salmo]

Like a certain beer, Glyphosate reaches the parts other ways of gardening cannot reach, but the real problem is that if you have couch grass and other nasties, you'll need to dig it all out anyway, so you might just as well knock down the foliage, by all means spray once, but then decide to start to dig a square yard at at a time...

The roots of plants treated with glyphosate are dead right to the tips of the roots. There is no need to dig them out. Anything that shoots after the initial treatment was dormant at the time of spraying and had no green leaf to spray. Those will need a follow up treatment.

Having said that some roots such as couch grass can be so numberous that they need removing by digging because they will not allow proper cultivation of the soil. But the digging and removal does not need to be so complete.

On the subject of weed seedlings, the old saying that one year seeding makes seven years weeding is very true. I like to see weeds germinating so that they can be hoed off when small. At least you then have fewer seeds left in the soil. That is why potatoes are a good cleaning crop. You get a chance to kill weeds before you plant and then kill more each time you earth them up.