When To Fertilize Again

[dwyndorf]

G'day,

 

I'm confused as to how often I should fertilize my plants. Do nutrients (Canna) dissolve after a while or are all the elements still present in the reservoir? Should I only be adding nutrients when I add more water? Whats the go?

 

dwyndorf

[Luke Skywalker]

If you are using a recirculating system then you should be dumping and reformulating your solution entirely every two weeks at least. Preferably every week actually. The reason is that the plants will draw up varying amounts of the different nutes as they require them.

 

So even if you have a fairly decent e.c. level after a week, the nutrients present will be unbalanced, and could cause nutrient deficiencies if it's used too long. Adding more nutes doesn't solve this problem either, as all you have is a balanced nutrient being added to an imbalanced solution... it may well overdose the plants on some nutes and never give enough to make up the difference in some others.

 

Remember, e.c. and t.d.s. meters will only measure the total dissolved salts, or the overall concentration, it won't tell you what specific amounts of what nutes are present.

 

So dump your nutes every week, and make up a new solution with fresh water and nutes. pH levels should be checked every day or so, to keep the solution in the ideal ranges for your system. pH which is too high or low will lock out nutes from the plants, and they won't be able to draw them up, even if they're there.

 

Oh, and on the adding water thing, you should always try and keep your reserviour topped up to a standard level each day, or as often as possible. The plants will draw on more water through the transpiration process than they will use nutes, so the concentration will drift upwards if you don't replace the water. Measuring the e.c. before and after topping up the res will show this most clearly.

 

A float valve which feeds fresh, pH adjusted water to the nutrient reserviour when it's level drops is a great way of automating the topping up of the res. You just have to top up the "feeder" res with fresh, pH adjusted water every week or so, depending on the size, rather than having to top up the nutrient res every day. Check out my recirculating hydro thread for some more info on this.

 

Hope that helps.

[dwyndorf]

Thanks Luke, you are the pope of dope That makes perfect sense, hopefully my bronzewhalers will be lovely.

 

Cheers

 

dwyndorf

[Luke Skywalker]

Always happy to help out dwyndorf.

 

And I'm a jedi, not a catholic. ::