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Hydroponics my way

Printed From: Sensi Seeds Shop
Category: Sensi Seeds
Forum Name: Nutrient, Fertiliser and pH
Forum Discription: Which kind, which dose, which stage?
Printed Date: 20 April 2019 at 16:59

Topic: Hydroponics my way
Posted By: Grasso
Subject: Hydroponics my way
Date Posted: 27 July 2007 at 03:32

everyone is free and can salt his meat in any way he wishes hence when I will write "toxic" I mean "toxic for me and the spirits swirling around me". On the other hand there are certain obligatory prepositions for plant growth, at least noone has found a way around them yet.

Hydroponics is about a clean machine and a ripe plant. Only the plant is organic while everything else is anorganic. For my first hydroponical CANNABIS grow I digged up some facts which shall be of use for the soil-involved grower, too.

My definition of organics is matter which cannot be assimilated by plants. Plants produce organical matter from anorganical matter and the energy of the sun. Animals, fungi and bacteries feed from organics. Most of these chemical-energetical transformations rely on the elements hydrogen, carbon and oxygen.

Human health is harmed by over-fertilized not-so-edible crops. Plants can accumulate far more minerals than needed (3) and then become prone to diseases such as grey-mould. Overshoot minerals are stored in vacuoles, the storage bins and rubbish dumps of plants. CANNABIS cultivation as teached by the sub-culture applies hundred times too much phosphorus.

P is not a primary but one of the six macro nutrient elements. Scientifical nutrient solutions since the nineteenth century reflect averaged element contents of plant matter. I do not have specifical data for hemp but for dozends of other herbs read in german (1) and (2)!

In soil plasma P often occurs with less than 0.1 ppm, still plants are growing vigorously. (4) Growing plants is easy and fun but responsible farming goes to great lengths to dial in the feeding needed for healthy growth.

A nutrient solution derived from "Plant physiology" by Taiz and Zeiger (1998) states concentration of element masses in water as parts per million:

N   30 ppm (25 ppm as nitrate, 5ppm as ammonium)
K   20 ppm
Ca 10 ppm
Mg 4 ppm
P   4 ppm
S   2 ppm
Si 2 ppm
Cl 0.2 ppm
Fe 0.2 ppm
Mn 0.1 ppm
B   0.05 ppm
Zn 0.05 ppm
Cu 0.01 ppm
Mo 0.0002 ppm
Ni 0.0002 ppm

Many people state ppm values of dissolved salts including their O and H atoms hence give numbers approximately twice as high. Nobles use mol / liter instead of ppm. Also confusing is that sometimes the electrical conductivity (EC) in Micro-Siemens or in conductivity factor (CF) is given instead.

Some elements dissolve from the medium or are present in the tap water or as contaminations in the salts. Most plants including grasses, nettles, horsetail and hemp profit from silicium. Tea is fertilized with aluminium. Some algae and nitrogen-fixing bacteries need cobalt. Animals like us also need sodium, selen, vanadium, chrome and possibly lithium, tin and fluoride in our diet. Plants also take up elements which neither they nor we need, for you know cadmium, plumb, mercury, silver and so on. Acidic water running through copper pipes may dissolve toxic quantities. Many plastics contain heavy metals. Excessive accumulation of metals in living beings, especially in fatty matter (the brain!) does occur.

Nitrogen should be supplied mostly but not solely as nitrate. An excess of ammonium could be eaten by microbes which release nitrite which other microbes turn into nitrate. Although plants do the opposite, using up to 1/4 of all their energy for the conversion of nitrate to ammonium which is then built into bigger organic compounds, free ammonium and nitrite ions can be toxic for living beings.

(5) shows that plants can adapt to many things, in this case the lack of nitrate. Plants can also live with thousand times more chloride than needed.

Most nutrient elements are mobile which means that the plant can draw them out of wilting and woodening matter and recycle them for fresh growth of leaves, fruits and roots. Nitrogen is very mobile. Potassium is drawn out of wilting matter( but locked up or still needed in wood). Ca, S, Fe, B and Cu are rather immobile hence must be supplied until a few days before harvest. Falling leaves and wood contain much calcium sulphate known as gypsum.

Iron is that vital to photosynthetical cells that any overshoot is stored in special protein boxes. For sinsemilla and other green crops iron may lie inbetween a macro and micro element.

pH shall be around 6, providing some hydrogen fuel and keeping all ions dissolved. Fluctuations between 4 and 7 may be allowed (5), giving the plant a chance to play and adapt.

Dissolving minerals and keeping them dissolved can be tricky. Much depends on temperature, pH and element mixes, and steps must be taken in the proper order. Some calculations can be done but there are many rules. Solutions which have been stable for weeks may topple within a day. The reason is that once seeded crystallization speeds up with the third power.

When storing nutrient mixes "the lower the concentration the better" is not always a true statement: Bacteria may feed on organical compounds as used in soil fertilizer and as chelates. A high concentration may prevent their growth. Beer can go bad fast, wine less likely, liquor never.

Salt solutions are usually denser than plain water. In still fluids concentration gradients occur since diffusion is weak. "Shake well before use!" Gases show much stronger diffusion which is the reason why carbon-di-oxide emitted by power and chemical plants, heatings and breweries seldom suffocates anyone.

Most metal ions tend to precipitate (fall out) by reacting with phosphate and borate ions. The remedy is to supply two masses of fertilizer (A and B) which are diluted and mixed for each application. Chelates are needed for long-term storage of single-bottle fertilizers. Sea-grass extract is a natural mix of chelates, ions and hormones.

That's it for the basics. If you are still interested in how I found out and mess around then read ahead:

I made a solution of potassium base by washing out wood-ash and running the liquid through a coffee filter. Boiling off a full 100 ml Duran cylinder I obtained around 150 mg of KCO3 salt. This solution is neutralized with nitric acid before application. Calcium and other metals are dissolved by washing the filter contents with diluted nitric acid. While the fresh wood-ash was dirty white, the water-washed one was grey and the acid-washed one is black. The wood is from the countryside.

I tried to order nitric acid (HNO3) in several pharmacies but they asked me to sign papers and could not deliver it anyway. Certainly it is corrosive. All nitrates are toxic. Nitrite (NO2) is ten times more toxic than nitrate and gives bacon red colour and long shelf-life. In the end I ordered Canna pH-down Vega (38 percent nitric acid of food quality) online.

I bought 100 g of bitter salt (made up of 50 g of MgSO4 and 50 g of water) for 90 cents in a pharmacy around the block. As a peace-of-mind for essential trace elements and as the main source of phosphorus and ammonia I have a Substral Hydro bottle.

I dilute one part tap water by 3 parts rain water because of its calcium content. I top up the reservoir with solution when most water has been drawn. I rinse the medium and clean the bucket once in a while.

I also bought 100 pH 4.5 to 10 +-0.5 test stripes for 10 Euro. pH is for plants what dB is for hi-fi: Fractions do not matter. These sticks are medically approved for urine testing and will neither break when dropped nor suck out a battery. I also have a pipette for dosage.

I use a medium of perligran, sand and moss. Perligran consists of chunks of baken perlite, a foam of sand which retains gas and water. Strings of moss (sphagnum moss) retain water and keep the medium as one. Sand adds density and keeps the roots rolling. A pump gently waters the pot three times a day for some seconds. The drain runs back into the reservoir.

Plants respirate which means that they use up some of or all hydro-carbons to keep strong and alive all their little proteine factories. The higher the temperature the harder the defend of their order. Only one tenth of the energy produced by tropical plants is digested by animals, fungi and microbes. The rest, much of that at nights, is used for maintenance.

Plants show many responses to heat and light. In hot sunny days forests emit organic gases. Many reactions are triggered by blue light exclusively hence one would not believe that plants grow under orange light at all!

I am not a chemist and can merely calculate the mass of sulphur in a certain mass of magnesium sulphate. I cannot calculate electron transfers, say how easily certain ions react with each other and fall out, yet.

Some of this information was found on the german aquaristics website
4: Plant physiology by Taiz and Zeiger (1998)


Posted By: Grasso
Date Posted: 31 July 2007 at 21:21
Hello folks,

I updated the article above. The most striking news is that phosphorus is a secondary element, only needed in rather small amounts. Too much of it weakens the plant. Strong plants do not need any shelter, dehumidifiers, heaters or HPS lamps. Although CANNABIS has been sucessfully grown in Goa and Columbia it still is a species of the temperate climate. Farmer Mick could grow his ERSB bud on his Irish balcony if he only gave them the right diet.


Posted By: farmer mick
Date Posted: 31 July 2007 at 23:19
If he only had a balcony! Smile

Posted By: Grasso
Date Posted: 19 August 2007 at 01:15

the great response encuraged me to give some practical examples and critics. Half of the advertizing in grow magazines is about fertilizers hence there must be some interest.

By suppliing plenty of potassium and no calcium I made the pollinated buds stretch. Sinsemilla buds were not affected. Since I started to supply calcium the plants have regained health and draw less water than before.

Nitric acid is very powerful and agggrrresssive, in one word caustic which is greekish for burning. Fortunately my household-cleaning rubber-gloves resisted it so I can still type this.

Let us have a look at the Hesi Hydro Grow fertilizer:

It shall amongst other elements contain calcium, phosphor and sulphur. But how does this work when calcium phosphate and calcium sulphate are supposed to fall out? I mixed bitter-salt into a weak solution calcium nitrate, heated it in order to simulate long-term storage, and gypsum fell out indeed. At there is a long discussion of precipitation. Organical fertilizers ("bio" brand bottles) do not have this problem since the calcium can be chelated (sat into an organic complex compound).

The Hesi Hydro Grow stuff is declared as "30+14+25" and "30 percent nitrogen" on the english label and as "NPK 30+14+25" on the german one. But ammon-saltpeter (NH4-NO3) contains less than half nitrogen, and fuming nitric acid contains less than a quart nitrogen. Hesi claim that at least 69 percent of their fertilizer is made up by nutrient elements while in reality at least 69 percent are made up of ions. Big difference! Now Hesi add the foot-note "EC NPK - fertilizer 12+4+8" on the english label and "EEC NPK Dünger" on the german one.

Hesi add vitamins, plant sugars and amino acids but list them at last, after the trace elements. So are these homoeopathic doses? If so then do homoeopathic doses really help, or do Hesi just happen to know how to treat instable personalities like mine?

Lastly let me critizise the usual fertilizing sheme as given in . Why the sudden change in nutrient composition between "growth" and "bloom"? Why the rising concentration of PK 13/14 in "bloom" until a sudden drop-dead of all nutrients one week before harvest? Hurry up, Santa Claus has not yet received your wish-list! I use a weak Hoagland solution throughout the grow and do not flush at all.

The sudden jump in photoperiod is a strange cultivation habit, too. This jump in conjunction with rooting stress made my fiber-drug hybrid cutting grow pollen. At fault is not the sensitive plant but rude Grasso who in his fear that the plantlet might not root missed the chance to reduce the photoperiod gradually over several weeks.


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