Niggle about measures

[ken]

I bought some B&Q concentrated tomato feed this year. The plastic contaner has a typical shallow, wde cap. The instructions are one and a third capsfull in 2 galls of water. Who is goingto faff around trying to measure a third of a capfull?
Similarly, I had to make up some derris last night tospray against gooseberry sawfly. 5ml in 2 pints. So, after I had thooughy sprayed the one gooseberry bush and one red currant bush (which, incidentally, has suffered more damage than te gooseberry), I'm still left with one pint of made up derris to pour away.
You'd think manufacturers would consider how consumers might use their products in real life a little more carefully, wouldn't you?

[FelixLeiter]

5ml in 2 pints

This does actually make the manufacturers look like morons, mixing metric with imperial. Who do they think they are, NASA? I see this a lot on the instructions for garden chemicals. It is completely unacceptable, in my view. If a pharmacist or industrial chemist did this, there would be consequences.

[ken]

Of course you're right, Felix. In fairness, the instructions for the derris say "5ml in 1.1 litres (2 pints)". The 2 pints mark is very clear on my sprayer, whereas 1.1 litres would be a bit of guesswork...

[heyjude]

Does anybody know how 35g of Bordeaux mixture might translate into teaspoons? I have got metric weights for the kitchen scales but the scales are a bit big.

thanks

[Johnboy]

Hi Jude,
The answer is 1.23 ozs but how you measure the 0.23 is very much open to question. My scales are in metric and imperial but they are not that accurate and but I have some other scales which were for batching and I have a 1oz and a 1/4oz weights and 1/4oz is a one penny piece and a 5 penny piece. I am not sure if this is of any use to you but I am trying.
(very trying)
If I were to pop over to you I could bring my scales so that you can get a receptacle so that you do not have to measure by weight but by volume.
JB.

[alan refail]

Hi Jude

Now I'll try to be as trying as Johnboy

You could play with this handy calculator - if you can figure out some ingredient that weighs as much as Bordeaux mixture.

Or, of course, you could weigh out 100grams and use a third of that.

[heyjude]

The thought of you two competing to be trying...........

I'd thought of weighing 70g (which would make 3litres) and estimating one third to get a litre which would go in a spray bottle but what I would really like to do is get a volume that I can easily fish out of the tub so that I don't have to scrape a tiny bit of powder out of a big old fashioned scale pan.

Johnboy, you could come and admire the tunnel as well! I'll mail you.

thanks to both

[richard p]

i never worry that much, the quantities in the instructions are a precise figure, but in real life a 20% variation isnt going to make a jot of difference to the results when the solution is used. in many cases you will find the figures given on the pack make a much stronger solution than is actually necessary... they sell more product that way.

[heyjude]

That makes it much easier - I can use a thin plastic pot to weigh the powder and then know how much to use in future (by nice, portable volume) and err on the side of weaker rather than stronger.

thanks

[Johnboy]

Hi Richard,
The trouble is that very few weighing scales can very accurately measure an ounce and the thickness of the pointer on the dial is probably 20% either way and when dealing with chemicals accuracy is all!
I suspect that your cynicism regarding manufacturers is very ill founded as usual.
JB.

[richard p]

jb may i respectfully suggest that if you want to weigh an ounce you should use a decent set of kitchen scales not a weighbridge for a forty ton lorry.

[Johnboy]

Richard,
You can respectfully request anything you care to name of me but do I need to say anything further!
JB.

[JohnN]

A letter in this morning's newspaper says that a 35mm film canister holds exactly 35ml of fluid. (Checked, and found correct!). Hope this helps. John N

[peacocks]

You will find digital scales will give a more accurate reading than the dial type.

[heyjude]

Thank you all for your suggestions.

What we did was use JB's small balance. Presumably my big kitchen scales would work as well (after all a balance is a balance) but it would have been clumsier and I was grateful to use a balance that is hardly bigger than the chemical balance I used at school.

We balanced a lidded plastic pot with various small coins. Then we added 35g from my kitchen metric scales (to the coins). Then we spooned the powder into the pot until it balanced again. Then we marked the level on the pot. So now I have a measure that I can use again.

Meanwhile the raspberries are thriving and more fruit is appearing at different heights on the canes so it has got harder to spray the lower leaves without catching the fruit. Last year the rust only took hold fairly late in the season, so I think I will wait until we have finished picking and then spray the leaves.

So thanks again to you all