Diluting fertiliser to use in a pond.

I have a pond fertiliser than requires a dilution of 50ml to 1,000 litres of water. My pond is tiny and only holds 20 litres of water. This would require 1ml of solution. That is too small an amount for me to accurately measure using what I have to hand. How would I go about diluting the full-strength solution so that adding 10ml of the diluent would be the same as adding 1ml of the full-strength?
Is it as simple as 10ml of fertiliser to 90ml of water then add 10ml of this to the pond?

 

What are you fertilising in the pond?

Go to the chemist and ask for a syringe.

 

If you have kitchen scales, it's easiest to do by weight. Tare the measuring jug and pour in 50ml. divide the weight by 100, rinse and dry the jug and drop in the necessary amount of drops to get the right concentration for 10l. Fill the jug with water, pour into the pond and repeat to treat the full 20l pond.

Or just drop in a drop or two, in real life the measures are just guidance as the need depends on external factors such as temperature, amount of vegetation, any organic material already in the pond, and light. Overfeeding will kill, but underfeeding is often quite ok.

A teaspoonful is about 5ml and 10 drops of water is about half a ml.

 

As said, you need 1ml per 20ltrs of water, which is approx 20 drops, though always put the drops onto a spoon rather than over the pond in case the lid comes off etc !

Pond fertilisation is not an exact science as its uptake depends on the plants in your pond.

If you only have a few plants in there we would suggest you only add a quarter dose eg 5 drops at the interval specifed on your particular product.

In planted aquarium tanks where its often hard to say what the exact needs are, a commom practice is to give a full dose each week, but before each dose, remove and replace 50% of the water with fresh declorinated water, so this avoids any eccess build ups of the fertiliser salts etc.

Edit - you do not mention what plants etc you have in your minature pond, but probably we would not bother with any fertilisation as the wildlife will add more than enough anyway, eg bird droppings, creatures that inhabit the pond or bugs that drop into the water and drown.

 

The plants in the pond are Nymphaea “Pygmaea Rubra”, Hippuris Vulgaris, Pontederia Cordata “Alba” and Lobelia Cardinalis. One of each. We also added some Hornwort. It has been established for 6 months now and seems to be doing fine.
I have just ordered a box of 3ml disposable pipettes so I will dose it with them.
That was a good tip about changing the water. I did that with my aquarium but never thought of doing it with the pond. I'll syphon some water out and top it up with water from my water butt.

 

Wow, not sure how all those plants fit into 20 ltr now , let alone grow up to their usual size ?
That water lilly is said to need a decent level of water above it to grow properly ?

Also wonder how such a small volume will cope in the hot weather, it could literally cook the plants if in direct sun all day ? ( and yes have been in Edinburgh on hot days! )

Have just started a new small pond ourselves, a 50cm round pot but 40cm deep , about 80 ltrs and would think those plants would soon fill it up.

 

It came as a kit from Pond Plants UK. They have been going for a long time so I assumed they would know what to supply. It is our first time trying a pond hence we bought the kit. The bit I read about “Pygmaea Rubra” said 4" to 12" of water in full sun! It seems to be happy at the moment so I will just need to see how it goes.

 

Be interesting to hear how it works out, as would a picture if possible.

Can you take it indoors/frost free during the winter as such a small volume could freeze solid and possibly kill the plants if not protected etc.

 

There were a few times last winter when it froze over but just a skin. It doesn't get that cold here.
This is the only photo I have with the pond in it.

 

Changed some of the water this morning and then added 1 ml of pond fertiliser. Later in the afternoon, I set the thermometer up in the pond. With an air temp of 22°C, the water in the pond was 25°C.

 

Must confess we tend to let any pond get on with its own thing these days, the wildlife seem happy enough with it.

We had to start off this temporary one as the old ones liner was leaking too much, so needed somewhere for the frogs etc to hide.
Almost all the plants in the old pond were so big it was not possible to put them in this little tub, will have to see if the local shops have any new plants left.

This pots calculates out at about 80 ltrs ( 50cm x 40cm deep) and does not seem much bigger than yours, your 20 ltr sounds very low for what looks a good size pot ?

 

The pond is 40cm x 27.7 cm. Taking it as a cylinder that is 22 litres so allowing for the slight taper I settled on 20 litres approx.