Concepts of mineral nutrient solution. Why do we fertilize plants?

[HolyGrailP]

I wanna hear more about it.

I guess so.

I bought masterblend tomato formula and was planning to go synganic route. What do you recommend regarding watering and feeding if I couldn't practice steering, the regular old wet and dry cycle? I was also told to master root development by a farmer. How can I do this with what I have available right now. Am using fabric pots btw.

General tomato solution can be quite heavy in N and K. Just keep in mind for cannabis.

Yesss, root development is worth it if you are going a long cycle and I guess that is your case as you are growing one full season a year at outdoor?
However, keep in mind if you are running a short cycle it is the opposite as forming root is also energy usage for plants. Anyway, you force feed via pressure and mass flow so no need of massive root for this case.


Get to the point
If you are using pot, maybe you can consider using substrate like Coco, especially if your soil isn’t good. But if your soil’s favourable to you stick with it. Must make it uniform as possible in each pot tho.

About watering stuffs, first of all you should know how much is your max saturation point of your growing medium. Also, give same volume of watering every time. Just change in frequency of watering.

For instance, let’s say you have
10L of coco in pot and it has 40% max sat. It means it can hold up to 4L and if more water is given it will drain.

So once you fully saturate your substrate, you can start logging.
Let’s say your shot volume is 200ml.
And make scenario that you had to give 10 times of water to see drain with drain amount of 100ml.

Meaning your substrate water content was

4L (max holding capacity) -2L (10times of 200ml shot) +100ml (drain)
=2.1L

That is 2.1/4 =52.5%

before watering.
One important thing to mention is that careful false drain. If you water too quick, your nutrient solution will straight drain and you’ll be measuring your nutrients, not the drain.

Few more details
1. Water around an hour or two after sun-rise. It’s like giving water once plants are fully awake and fully working.
2. Water regularly. For example, 2CC of water for every 1J of energy accumulation in 1sqmt. However, if measuring radiation is limited, I would stick with smth like giving every 15mins via water pump +timer. If you want to hand water it, perhaps you can increase shot volume and decrease frequency. Make it regularly anyway.
3. Try to get constantly same or similar EC and pH in your drain. If drain EC starts going up you can increase shot frequency. If drain EC starts going down you can give last shot of the day earlier than normal so less shot frequency.
4. For pH, it’s mostly either dead root affecting it or nitrate:ammonium ratio affecting it. Will come to that in the future when you encounter the problem. Because to do that you need to be able to make your own nutrient solution.
5. Just an extension of (3) and to give a tip, if your first drain is getting lower, means that EC will increase so you have to water more and vice versa.
6. High drain EC will trigger generative action and low drain EC will be more on vegetatice action.
7. If you see plants head (top of plants’ stem) is thickening or stem is turning purple, plants are heaving too much sugar. Also means vegetative action. You want to avoid that during flower tho cuz vegetative action slows down flowering. In this case, would increase temperature or decrease light amount per day but for you the best bet is increase source so plants waste more sugar.
Vise versa.


** Last but not least, keeping it regular practices are the most most important thing. When plants are in new environment they are stressed. They use energy to adapt in new stress. Meaning you’ll lose yield as plants use energy to recover not grow. So regular practices are the most important thing.

I think this method can be suitable to your case. However, each different cultivar (strain) or cut will have different water uptake speed so if you want to minimize your labour, you can minimize number of your strains and prepare cuttings with uniform size as much as possible.

 

[Ca++]

The local farmer knows the land, and it's sandy composition is likely why he speaks of good root development. Weather conditions I'm unaware of could also play a part in this. Where late season, plants may need to of reached down and out to survive.
This doesn't tie in with fabric pots very well. The concept of a dry back could be lost. Roots last about half an hour once dry. The outsides may dry very fast, and so you are having to grow new roots more than planned. In late bloom, this possibly can't be done. I have no first hand experience with the circumstances, but it almost sounds like a constant drip would work. Perhaps a re-circ system. To get it wet enough and avoid the uneven drybacks of the fabric and sand.

I might be showing bias, but I don't see fabric pots as a cannabis thing. Except for cost and their disposable nature. With a sandy soil, the balance is really tipped. Though how sandy is sandy, I don't really know.

 

[marwachine]

The local farmer knows the land, and it's sandy composition is likely why he speaks of good root development. Weather conditions I'm unaware of could also play a part in this. Where late season, plants may need to of reached down and out to survive.
This doesn't tie in with fabric pots very well. The concept of a dry back could be lost. Roots last about half an hour once dry. The outsides may dry very fast, and so you are having to grow new roots more than planned. In late bloom, this possibly can't be done. I have no first hand experience with the circumstances, but it almost sounds like a constant drip would work. Perhaps a re-circ system. To get it wet enough and avoid the uneven drybacks of the fabric and sand.

I might be showing bias, but I don't see fabric pots as a cannabis thing. Except for cost and their disposable nature. With a sandy soil, the balance is really tipped. Though how sandy is sandy, I don't really know.

I will take pics of the soil when it's really dry. I live in the tropics btw. I've seen Kevin Jodrey telling people to saturate the medium to full capacity then wait until it's around 50% moisture before watering again. He sounds convincing but my problem is how can I tell if the soil is around 50% to start the watering.

 

[HolyGrailP]

The local farmer knows the land, and it's sandy composition is likely why he speaks of good root development. Weather conditions I'm unaware of could also play a part in this. Where late season, plants may need to of reached down and out to survive.
This doesn't tie in with fabric pots very well. The concept of a dry back could be lost. Roots last about half an hour once dry. The outsides may dry very fast, and so you are having to grow new roots more than planned. In late bloom, this possibly can't be done. I have no first hand experience with the circumstances, but it almost sounds like a constant drip would work. Perhaps a re-circ system. To get it wet enough and avoid the uneven drybacks of the fabric and sand.

I might be showing bias, but I don't see fabric pots as a cannabis thing. Except for cost and their disposable nature. With a sandy soil, the balance is really tipped. Though how sandy is sandy, I don't really know.

Ahh I get your point
Yess and I would really recommend to use soil analysis if anyone wants precision agriculture.

Tho what local farmers assume and what actually is in soil are sooo far from each other.
At least, most of farmers in the Netherlands do soil analysis but then they are doing it for living not hobby.

So again, it depends on hobby level I guess
If one’s aim is to finish plants life cycle, why over complicate
But if one wants precision agriculture better complicate it

 

[Ca++]

I will take pics of the soil when it's really dry. I live in the tropics btw. I've seen Kevin Jodrey telling people to saturate the medium to full capacity then wait until it's around 50% moisture before watering again. He sounds convincing but my problem is how can I tell if the soil is around 50% to start the watering.

You fill the pot and weigh it. Lets say it was 10kg.
You water the pot until saturation, and weigh it. Using HolyGrailP's example again, lets say that was then 14kg.
Your water holding capacity, is 4kg.
Bu weighing the pot, you can see when 2kg has gone.
Very soon, you won't need the scale. Though you will the first year, as you see what plants add to the weigh-in. And how roots effect the holding capacity. Learning it's really about weight and touch together.

In your fabrics, you probably can't do it. The outside will get overly dry, killing the roots in that area. These will then need growing again, so you are growing roots not plants. Once after stretch, the plants focus moves from roots, and as such you just end up with a compromised root system. One open to mold attacks, more than you want.

I just don't like fabrics, and your sandy soil and hot climate, are not going to help matters.



Soil tests are great. I did my outdoors plots. It allowed me to correct what I had, so for a few years I can use suitably balanced commercial feeds. Before this, I was carrying in a few bags of compost, and now just a kg of appropriate feed stuffs. Making the yearly pilgrimage a 3 hour job, with a basic rucksack.
I checked about 6 sites, and only handed over a couple of hundred.

 

[HolyGrailP]

You fill the pot and weigh it. Lets say it was 10kg.
You water the pot until saturation, and weigh it. Using HolyGrailP's example again, lets say that was then 14kg.
Your water holding capacity, is 4kg.
Bu weighing the pot, you can see when 2kg has gone.
Very soon, you won't need the scale. Though you will the first year, as you see what plants add to the weigh-in. And how roots effect the holding capacity. Learning it's really about weight and touch together.

In your fabrics, you probably can't do it. The outside will get overly dry, killing the roots in that area. These will then need growing again, so you are growing roots not plants. Once after stretch, the plants focus moves from roots, and as such you just end up with a compromised root system. One open to mold attacks, more than you want.

I just don't like fabrics, and your sandy soil and hot climate, are not going to help matters.



Soil tests are great. I did my outdoors plots. It allowed me to correct what I had, so for a few years I can use suitably balanced commercial feeds. Before this, I was carrying in a few bags of compost, and now just a kg of appropriate feed stuffs. Making the yearly pilgrimage a 3 hour job, with a basic rucksack.
I checked about 6 sites, and only handed over a couple of hundred.

Love it