How to grow cannabis in Coco Coir (hydroponic)

[BritManToo]

There are many challenges to growing quality hybrid cannabis in Thailand. the greatest being no suitable soil.

You need a light soil, with little in the way of nutrients. All the potting soils and 'din dee' I have found contain high levels of unknown fertiliser that burn your plants roots.

So I grow in G4 Coco Coir perlite mix, this chap sells the complete mix, enough for 2-4 big pots around 200bht.

https://shopee.co.th/วัสดุปลูกรวมชุด-เพอร์ไลท์-เวอร์มิคูไลท์-พีทมอส-5*-1*-10-ลิตร-(แบ่งบรรจุ)-*สามารถปรับปริมาณ-เพอร์ไลท์-เวอร์มิคูไลท์-i.193303481.4004570476?sp_atk=5683ae19-efd0-449b-b8d7-0989de8d3ef0&xptdk=5683ae19-efd0-449b-b8d7-0989de8d3ef0

You will also need a PH pen (100bht) and chemical fertiliser,

https://www.lazada.co.th/products/i3143669263-s11722895229.html

Wesco 30-20-10 for veg (125bht)

https://www.lazada.co.th/products/1-wesco-30-20-10-te-i294906795-s495848547.html

Wesco  0-52-34 for flower (250bht) 

https://www.lazada.co.th/products/wesco-0-52-34-1-i3284837794-s12188013737.html

And Citric acid crystals to adjust the PH of your liquid fertiliser.

 

Mix the Coco and perlite together, wet the mix thoroughly, place in a 3l or 5l cloth pot and you're ready to plant your Jiffy pellets (vermiculite is used to sprinkle on the top to discourage insects burrowing into the mix. Water around the pellet, never on the plant until water drips through the bottom of the pot.

There are no nutrients in the coco so after day one you need to fertilise EVERY day. It takes me around 20mins/day.

 

Veg phase, (if in a tent 16-18hrs of light/day)

Day 2 mix up your 30-20-10 fertiliser as directed on the packet, put your PH pen in the mix, it should be 5.6 (a bit either way as acceptable), water in Thailand is normally 7 or above, so stir in a few citric acid crystals well then test with the PH pen again (a small pinch of citric acid makes a big change so a little at a time).

Once the Ph is correct water around the plant (never on the plant) until it drips freely through the bottom of the pot.

This needs to be done every day.

 

Flower phase, (if in a tent 11-12hrs of light/day)

Mix up your 0-52-34 fertiliser as directed on the packet (don't assume the same mix as the previous fertiliser), again you need to adjust the PH, this time to 6.1 with a little leeway in either direction. Pour around the plant, never on the plant.

 

Sometimes Coco coir is washed in salt water, this isn't suitable for your plants, the supplier I suggested provides a perfect product, the compressed plastic wrapped 5Kg bricks are also usually OK. 

 

Big advantage of Coco, you can't over water your plants, any excess drips through.

Over watering is the easiest way to kill cannabis plants.

 

 

 

[GeorgeCross]

thanks, great guide!

 

do you have any recommendations for lights for a grow of that size?

 

 

[BritManToo]

6 minutes ago, GeorgeCross said:

thanks, great guide!

do you have any recommendations for lights for a grow of that size?

Hlg 240 + quantum board.

Perfect for a 4x2 tent, under the stairs, or just free standing in a room, 5,500bht.

https://www.lazada.co.th/products/led-grow-light-hlg-samsung-lm301h-v3-120240320480600-watt-meanwell-driver-indoor-grow-light-full-spectrum-full-spectrum-led-plant-grow-light-i1540904841-s4105096069.html

 

Cheaper on Shopee at 5,000bht

https://shopee.co.th/HLG-240W-SAMSUNG-LM301B-3000K-4000K-MIX660NM-UV-IR-i.258674463.8952653530

 

(careful to buy one with the meanwell driver, some shops just sell the LED without a driver)

 

[internationalism]

this linked by you 0-54-32 fertiliser is 300b per kg (including p+p).

How easy and safe is to store 25kg bag, which is 2600b for 25kg so just over 100b/kg?

How many months flowering season lasts?

Say with 10 plants and 2 litres per plant means up to 50g daily so around 1.5kg per month.

https://www.lazada.co.th/products/0-52-34-25-i251755470.html?spm=a2o4m.searchlist.list.22.4d224de72tCf6x

[BritManToo]

16 minutes ago, internationalism said:

this 0-54-32 fertiliser is 300b per kg.

How easy and safe is to store 25kg bag, which is 2600b for 25kg so just over 100b/kg?

How many months flowering season lasts?

Say with 10 plants and 2 litres per plant means up to 50g daily so around 1.5kg per month.

https://www.lazada.co.th/products/0-52-34-25-i251755470.html?spm=a2o4m.searchlist.list.22.4d224de72tCf6x

The bags I showed will last 1 year or more for a constant grow of 4-6 plants.

I grew 20oz using 1/3 bag of each fertiliser, really not worth buying in bulk.

 

Usually the grow is 1/3 veg and 2/3 flower depending on how big you want your plant (4 months in all). The flowering plant will usually end up being 2x to 3x the size of the veg plant.

So if you switch to flower when your veg plant is 2ft high, you'll end up with a 6ft plant.

 

If you use autoflowering plants, you get no say in the size, they do their own thing and you usually end up with 1oz per plant. With fem photo plants, the sky's the limit.

[Mr Meeseeks]

I was waiting for this thread. Thanks BMT. ????

[stoner]

this is going to be fun. i have my doobs ready. play on players. 

[blackcab]

Moved to the Cannabis Forum.

[jaideedave]

BritManTooSmall 2.5x2.5x5 tent indoors  Mars Hydro 1000  watt led. (autos)

I've been struggling for about 1.5 yrs to get thru a grow without any issues.

I tried many of the 420 soil mixes locally and always have issues near the end.(autos) I suspected root issues.I'm keen to try your coco mix idea.I'm familiar with the Wesco brand as I've used for veggies before. BTW..I have a small fortune in organic nutes (Gaia Green) etc. Would there be any issues using those for top dressing for example? I need to do a little more research in using organic in coco medium. TNX ..you're a great source of info... 

[BritManToo]

20 minutes ago, jaideedave said:

BritManTooSmall 2.5x2.5x5 tent indoors  Mars Hydro 1000  watt led. (autos)

I've been struggling for about 1.5 yrs to get thru a grow without any issues.

I tried many of the 420 soil mixes locally and always have issues near the end.(autos) I suspected root issues.I'm keen to try your coco mix idea.I'm familiar with the Wesco brand as I've used for veggies before. BTW..I have a small fortune in organic nutes (Gaia Green) etc. Would there be any issues using those for top dressing for example? I need to do a little more research in using organic in coco medium. TNX ..you're a great source of info... 

As long as you can make liquid fertiliser with them, any nutrient brand will work (with correct NPK).

I always use the cheapest fertiliser ......... WESCO.

Hydroponics rely on no fertiliser except the liquid you pour through every day. No top dressing.

 

And you really need to adjust the PH of the liquid before you pour it through.

Making up a weeks worth doesn't work, as the PH changes when it's sitting around.

PH pen and citric acid crystals are essential to get the correct PH (5.6-5.8-6.1-6.3).

Mix your nutrient solution, adjust the PH, water around the plant (never on top of the plant) until the nutrient mix drips freely through the pot base.

 

Everyone has their own idea for the correct PH to grow cannabis in Coco ...... near to 6 seems to work for me. Probably 5.6-6.3 are the outer limits.

[jaideedave]

BMT: Thanks so much for the reply. I now realize that top feeding won't work.I can make a tea from the organic nutes on hand.I'm quite familiar with PH pen use. Next Q ..about what PPM should I shoot for? under 2000 PPM?

Yes there is a lot of controversy around coco use but I'm at my wits end as to why my plants never finish well.I always suspected root issues but don't know how to remedy.I'm now using 3 gal fabric pots, should I go to 5 g in my small tent? I'm giving your method a go and see what happens, its cheap enough to try... PS:I'll probably go with Wesco nutes to start for simplicity sake...

[BritManToo]

1 hour ago, jaideedave said:

Yes there is a lot of controversy around coco use but I'm at my wits end as to why my plants never finish well.I always suspected root issues but don't know how to remedy.I'm now using 3 gal fabric pots, should I go to 5 g in my small tent? I'm giving your method a go and see what happens, its cheap enough to try... PS:I'll probably go with Wesco nutes to start for simplicity sake...

I'd go with 3 for autos, the plants never get that big, and you're pouring nutrients through every day, I find the 5s a bit heavy to move around).

I just use the mix levels suggested on the back of the WESCO packet and forget about PPM/T.D.S. I did use a T.D.S. pen a few times, think it was 300-500.

I chucked in 1/2 cap of cal-mag once a week as well, but not convinced it did anything worthwhile (the WESCO 30-20-10 contains trace elements).

 

I did a couple of autos, but didn't find the crops worthwhile.

 

[starky]

Very nice thread Britman. We have similar systems I also like to play with internodal length so I generally throw some giberrellic acid in the mix as well. ????

 Now that we can actually talk about this. I think this thread should be pinned for everyone to enjoy.

 

[cleopatra2]

On 6/16/2022 at 7:33 PM, BritManToo said:

I'd go with 3 for autos, the plants never get that big, and you're pouring nutrients through every day, I find the 5s a bit heavy to move around).

I just use the mix levels suggested on the back of the WESCO packet and forget about PPM/T.D.S. I did use a T.D.S. pen a few times, think it was 300-500.

I chucked in 1/2 cap of cal-mag once a week as well, but not convinced it did anything worthwhile (the WESCO 30-20-10 contains trace elements).

 

I did a couple of autos, but didn't find the crops worthwhile.

 

The Wesco do not contain all the macro nutrients, such as Sulphur and Calcium. It appears that magnesium is provided but i have not done the calculations to determine the amount.

 

I can only presume that ypur water has sufficient Calcium  and Sulphur to provide for the plants needs.

 

 

 

[Smithson]

Great info. How difficult is it to grow indoors here with the heat and humidity? Is it just a matter of air con 24/7? Do the LEDs perform well compared to HID?

[BritManToo]

28 minutes ago, Smithson said:

Great info. How difficult is it to grow indoors here with the heat and humidity? Is it just a matter of air con 24/7? Do the LEDs perform well compared to HID?

Really easy, I never bothered with air-con, just left the tent open in the day.

Don't know anything about HID, always used HLG 240 + Quantum boards (x2).

Avoid the scam 'burple' lights, they're worthless.

[Smithson]

So just a fan in the tent? What temps are you running at? And hand watering?

 

[BritManToo]

19 minutes ago, Smithson said:

So just a fan in the tent? What temps are you running at? And hand watering?

I have 1/2 dozen 12cm computer case fans dotted around the tent (run from a 12v phone charger). This grow was 32-35c most days, sometimes up to 40c.

The LED driver sits on top of the tent (not inside), and on most days I just leave the tent open, I only close it at night when flowering.

 

A bit later, the 2 autos in the middle (front Amnesia, rear White Widow) got moved outside the tent, and the 2 plants either side (Critical Orange Punch) became a 'Screen of Green'. It all got a bit too big ...........

 

Hand watered once every day with nutrient solution adjusted to PH6 (ish).

About 20-30 minutes off work, once a day.

[Smithson]

1 hour ago, BritManToo said:

I have 1/2 dozen 12cm computer case fans dotted around the tent (run from a 12v phone charger). This grow was 32-35c most days, sometimes up to 40c.

The LED driver sits on top of the tent (not inside), and on most days I just leave the tent open, I only close it at night when flowering.

 

A bit later, the 2 autos in the middle (front Amnesia, rear White Widow) got moved outside the tent, and the 2 plants either side (Critical Orange Punch) became a 'Screen of Green'. It all got a bit too big ...........

 

Hand watered once every day with nutrient solution adjusted to PH6 (ish).

About 20-30 minutes off work, once a day.

But you need to be there daily. I've known ppl who've had houses burn down, but if the set up is small it's safe enough

[Bobsuruncle]

5 hours ago, BritManToo said:

I have 1/2 dozen 12cm computer case fans dotted around the tent (run from a 12v phone charger). This grow was 32-35c most days, sometimes up to 40c.

The LED driver sits on top of the tent (not inside), and on most days I just leave the tent open, I only close it at night when flowering.

 

A bit later, the 2 autos in the middle (front Amnesia, rear White Widow) got moved outside the tent, and the 2 plants either side (Critical Orange Punch) became a 'Screen of Green'. It all got a bit too big ...........

 

Hand watered once every day with nutrient solution adjusted to PH6 (ish).

About 20-30 minutes off work, once a day.

Nice looking garden!

[BritManToo]

I now have 3 seedlings potted into peat. (Peat and Coco are both hydro mediums, no nutrients in them, you have to add in the water every day)

 

I'm putting them out in the early morning sun every day until 10am, when they get moved out of the direct sunlight. I already managed to burn the tips of Wiang Ping's first leaves when I left them out until 11am, no serious damage.

 

I'm using WESCO 30-20-10 +TE, 5ml mixed in with 2l of tap water, stir well, measure the PH (mine is 6.5) then reduce the PH to 6 by stirring in a small amount of Citric acid crystals. Water around the plant (never on it) until water drips through the bottom of the pot. That 2l will probably last me 3 days on plants this small. 

 

 

[BritManToo]

Already given up on outside, put my tent up yesterday afternoon and shifted everything inside. Tent open, settings 16hrs led, 24hrs fan. 

 

[jaideedave]

Hi BMT,

I've decided to give your style of growing a try.. I've seen where some folks have rinsed any residual salts away and charged it with some Cal-Mag > 300 PPM to help.

Do you agree with this. I realize some coir sources have more salt contamination than others.

I'm using the same Lazada vendor as you. Have you had any salt issues with is supply?

I'll be using your info as a guide. I'll have to get used to feeding every day though.

Will be starting an autoflower soon. Will keep you up to date.

Tnx

 

[BritManToo]

17 minutes ago, jaideedave said:

I'm using the same Lazada vendor as you. Have you had any salt issues with is supply?

If you're using the same supplier as me then it's Greenterra Peat. So no salt problems. If you're using the Coco blocks they've been washed, it's only the loose Coco that's sometimes salty and needs to be washed. Nothing wrong with adding a cap of Calmag to any of the hydro mediums. 

[cleopatra2]

1 hour ago, jaideedave said:

Hi BMT,

I've decided to give your style of growing a try.. I've seen where some folks have rinsed any residual salts away and charged it with some Cal-Mag > 300 PPM to help.

Do you agree with this. I realize some coir sources have more salt contamination than others.

I'm using the same Lazada vendor as you. Have you had any salt issues with is supply?

I'll be using your info as a guide. I'll have to get used to feeding every day though.

Will be starting an autoflower soon. Will keep you up to date.

Tnx

 

Coco coir has an high cation exchange . Which means that it holds onto the salts from the nutrient mixture. If not treated this will lead to a build up of nutrients in the coir and a change in the root zone ph.

Adfitionally because the coco coir is using some of the nutrients this leads to a nutrient imbalance and some nutrient lockout.

 

The purpose of the buffering / charging of the coir is to ensure all the nutrients in the feed is going to the plant and not partially being taken by thr coir.

 

[Bobsuruncle]

7 hours ago, BritManToo said:

Already given up on outside, put my tent up yesterday afternoon and shifted everything inside. Tent open, settings 16hrs led, 24hrs fan. 

 

BritManToo, I'm seeing about 5 small white gauges. What are you measuring or keeping track of? Light, Temperature, Humidity, CO2? I can't read the numbers. Thanks

[BritManToo]

1 hour ago, Bobsuruncle said:

BritManToo, I'm seeing about 5 small white gauges. What are you measuring or keeping track of? Light, Temperature, Humidity, CO2? I can't read the numbers. Thanks

Temperature, under 35c is good, my temps currently 30-33c.

[Bobsuruncle]

BritManToo, now that you've brought the seedlings back inside the tent under grow lights, what is the best distance that you would want the light to the babies? Is there such a thing as too close? You said that the sun was burning them after 10am when you had them outside, can you actually burn them under the lights inside?

Thanks for all this great information, it gives me a lot of confidence to start up a grow of my own.

[BritManToo]

13 minutes ago, Bobsuruncle said:

BritManToo, now that you've brought the seedlings back inside the tent under grow lights, what is the best distance that you would want the light to the babies? Is there such a thing as too close? You said that the sun was burning them after 10am when you had them outside, can you actually burn them under the lights inside?

Thanks for all this great information, it gives me a lot of confidence to start up a grow of my own.

It's very easy to burn seedlings, not so easy to burn fully grown plants.

I tend to keep my LEDs 18-24 inches from the green, at the moment the 240w LEDS are dimmed to about 30-40%. As the plants grow the lights get raised, and the intensity off the LEDs increased.

Here is this years grow ........ not much happening at the moment.

 

 

[bangkokairportlink]

On 6/14/2022 at 3:15 PM, BritManToo said:

If you use autoflowering plants, you get no say in the size, they do their own thing and you usually end up with 1oz per plant. With fem photo plants, the sky's the limit.

so we should not use auto flowering ?