Come on in – the water is lovely.
When growing hydroponically there are a few differences the grower needs to take into account, to ensure the plant gets everything it needs to not only survive, but to thrive and prosper its way to a happy, healthy harvest. An indoor grower takes over as God in the eyes of the plant, supplying absolutely everything necessary, and in just the right amounts to ensure success.

But like everything in life too much of a good thing soon turns bad and eventually the plants can die as a result of all the kindness bestowed upon them by the grower. This is often made worse when things go awry, and the novice grower ends up hurling lotions and potions at the plant in a bid to cure an unknown ailment, instead of dumping the reservoir and refilling with plain, Ph adjusted water (Ph 5.5).

This buys you time when using a method such as NFT, in which things can go seriously wrong, and very quickly.

There’s no more frustrating a time for a grower, than when he/she knows that everything the plant could possibly need has been provided, and yet the bugger refuses to feed, leaving the plant displaying deficiencies galore. Even worse if the plant runs into a dry wilt. Arse!

Osmosis

Before getting to grips with our theoretical situation there are a couple of things worth knowing regarding how roots do their stuff, and all will become crystal clear.

But the first thing to suggest would be firing up Google and doing a search for “Osmosis” (with the quotes). After the search completes, at the top right hand side of the page is a link called . Click it for a full explanation as to what osmosis really means. This will give an understanding of what we are trying to achieve in our role as Ganja-God.

Roots take up nutrients via the process of osmosis – in short, osmosis is the ability of a fluid or solution, to translocate through a semi-permeable membrane, thus equalising the concentration of the fluids on either side of the membrane. If one side of the membrane has a higher concentration of solution than the other, osmosis sorts it out and maintains the status quo. Science rocks huh?

Just think about that next time you put on your Goretex™ jacket, (Goretex - a semi-permeable membrane which allows sweat and condensation to pass through whilst keeping the rain out).

Your roots work in much the same manner.

Ok, that all sounds pretty straightforward. So let’s throw a spanner well and truly into the works by adding some provisos.

Locked out

In layman’s terms, if you are feeding a higher concentration of magnesium (e.g.), than that which exists within the roots, osmosis can (and will) work against you. Magnesium will be transported the wrong way, out of the roots and into the cubes/slabs (EC/Ph rising at run-off?). This condition will quickly manifest itself as a magnesium deficiency which is easily rectified with a feed containing a hit of Epsom salts.

Once the concentration in the solution is lower than that in the roots, the tide changes and the magnesium deficiency is soon cured.

But what happens if it isn’t cured? Here’s another spanner.The passage of” water”, through the semi-permeable membrane is controlled by either the TDS (total dissolved solids) or EC (electrical conductivity) of the nutrient solution.

So if the EC of the solution you’re feeding is higher than the EC currently in the roots, the plant will dehydrate by drawing water out of the roots and into the medium via osmotic action.

If using NFT and this proves to be the case, you can run your irrigation pumps 24/7 but the end is nigh through a dry wilt unless fast counter-measures are taken.

Taking the plunge
But it’s not all doom and gloom and if NFT was that easy everyone would be doing it, right?

It’s no accident that the growers who constantly succeed where others fail, are generally the ones who take the time to constantly monitor their water quality.

By taking regular readings of your Ph/EC values from the reservoir, as well as within the cubes/slabs and at run off, its easy to keep a track of how your plant is health wise and you can counteract these readings before any signs of ailing have manifested on the leaves.

Once the system is dialled there’s not a lot will get close to NFT yield-wise, but initially it can seem like you’re in at the deep end.

Hang in there.