Greenleaf Nutrients MEGA CROP Q&A/Support/Pictures/Feedback/Anything thread

Sponsored
#142

@Dabber68 is that auto cobs from BigSmO in US you’re using… 55w a cob.? I have two of them and they are handy as fk, placing them all at different heights etc… if not the same light it’s very similar…
Happy growing
Gaz

Edit : yeah @Dabber68, I thought so…, I’d have bought a couple more too if it wasn’t too expensive ( at the time i bought em) to ship etc… i have a 3K and a 4K and I’m using one for vegging with a couple more 28w led bulbs.
Looks like you have 4 … What height do you think best for these lights.? Any info you have on them- much appreciated mate.
Gaz

2 Likes
#143

Yes that’s what I have love them

3 Likes
#144

day 22 flower, feeding 15 to 16g per gallon w/ tapwater, LED grown in ~50/50 coco/perlite

image.png288×512 291 KB

10 Likes
#145

@legalcanada How big are the plants? That’s the most MC I’ve seen being used yet. They look great!

2 Likes
#146

between 36-48 inches from the soil, but i’m giving the same nutrient mix to my 2 smaller plants. feed every watering. it was every 2nd day at first but lately i’ve been giving them half as much every day instead. i’m seeing slightest tip burn on the big girls so i’ll probably hold it here a couple more weeks then start backing off. i generally start 4.5-5g at germination and increase from there.

here they are under 11w led bulb. the bigger one turned out to be a male and has been culled. the smaller one (3 bear OG auto) is now flowering underneath my 235w blurple.

20180329_152940.jpg4128×2322 2.44 MB

1 Like
#147

@legalcanada:

I guess it really is strain/individual dependent… I recently started some Tangie F2’s and Dinafem Blueberry off at 1g/gallon and the smallest of the blueberry still got a little burn on the tip. I anticipate needing to mix up separate batches for the Tangie and Blueberry going forward. But I will be ramping up the grams/gallon as they move along obviously. I just generally see people topping out at 8 or 9g per gallon, but some plants are just hungrier than others I reckon! Did the ones in the Solo cup start as clones or seed?

DISCLAIMER: This is my first grow with MegaCrop so I really am just going off what I hear other people saying.

:seedling: :sunglasses: :seedling:

2 Likes
#148

Question for those of you using meters with your mega crop - what TDS scale are you using?

Im asking because I just compared my readings using an Apera PC60 meter to the TDS numbers on the mega crop website feeding instructions, and my readings are way higher than what the webpage suggests they should be. I just checked and my meter came set to the 700 scale. Actually the TDS compensation factor came pre-set to 0.71

I have some feed water mixed at aprox 5.5 to 6 gm per gallon and it was reading 1310 PPM. The website says it should be in the 500 to 546 range. My water starts out at least 120-180 PPM, so I should be seeing 620-720 or so. So Ive been getting reading almost twice the calculated values from the website.

So, I changed the compensation factor to 0.50 (the 500 scale on some meters) and my water is now reading 701 PPM - which agrees close enough with the website’s calculated values.

Anyway, Im curious what scale you guys are using and what your TDS readings are at the dosage you are using compared to the website values.

I know the mega crop guys are working on a meter reading chart, and Im also curious what scale they are using.

3 Likes
#149

I’m using a meter that I believe is 500 scale, and at 6g/gal I usually get around 650ppm reading, after mixing with tap water that usually reads about 35ppm.

2 Likes
#150

have you recently calibrated your meter? this is why i just use EC it’s less confusing. they are probably using ECx500, i have ECx500 meter and i’ve only checked ppms once and i think 13 or 14g/gal in tapwater was 1750 or so

4 Likes
#151

Thanks to both of you for the feed back. Sounds like the number they have on the website need the 500 scale.

Yeah, I calibrate pretty often even though the meter has never been off significantly.

I agree that it would be good if more people used EC. Far less confusion, and no conversion needed. Unfortunately, the vast majority only use TDS. Also, many folks dont seem to understand the difference between PPM and PPT and dont even know there are different scales for TDS.

I still dont understand WHY there are two different scales in the first place. I saw a link several weeks ago showing which scale different nute mfg’s used and it was roughly split 50/50 between them using 500 or 700 scale. That doesnt help either.

2 Likes
#152

Feeding Chart ppm is elemental parts per million and not based around any meters.

3 Likes
#153

there are a lot more than 2 scales. you can’t actually measure PPM with a simple meter (only chemical analysis) so it measures EC then converts. the scale you use depends on what you’re measuring. 700 is for measuring potassium chloride and the 500 scale measures sodium chloride content. i guess it depends on which salt the nutrient company is using.

i’d guess megacrop uses sodium chloride, thats why 500 scale is more accurate

3 Likes
#154

H

Yeah, I gave you guys a real hard time about that several weeks ago, until I finally understood what you were saying - sorry about that!
How is it coming on the EC chart??

Here is a good link about EC vrs TDS and what different ‘scale’ each nute mfg is using.

http://www.gyostuff.com/What_PPM_Scale_To_Use.html

Mega Crop wont be on that chart because they calculate the PPM’s based on weight - not meter measurements.

2 Likes
#155

Ah! I did not know that. I had read somewhere that is was a US vrs EU thing, but this makes more sense.

Good info, thanks!

1 Like
#156

Now I feel stupid. I should have re-read the link I posted above - its all in there! :slight_smile:

2 Likes
#157

i guess it’s because some elements can have the same EC rating but different PPM values, so the meter does its best to ‘guess’ the PPM based on what it’s measuring. thats really cool your meter can change conversion factors, what meter do you have? for other people they can convert by either dividing by 700 then multiplying by 500 or dividing by 500 then multiplying by 700.

4 Likes
#158

I have this one - Apera PC60

The scale is adjustable from 400 - 1000 in one point increments, so yeah, there are lots of options.

They also make an EC60 that does every thing except PH, but I wanted PH too.

After getting past the initial learning curve, I like it a lot. Its staying calibrated very well.

2 Likes
#159

meters are pretty useful especially for getting the same numbers every time. So, for example if you mix 10grams of MEGA CROP into a formula, and find it gives you 650ppm on your meter, in the future you can measure by meter alone just using the 650ppm number. So you can save time by skipping measuring/weighing nutrients and just go off meters alone once you get dialed in.

I always had such bad luck with PH meters, they never worked well.

1 Like
#160

I went through several cheap ones before deciding I needed to spend a little more for a decent one.

2 Likes
#161

i guess that would also be handy for topping up a reservoir or something, no measuring water or weighing nutrients just top it up with a hose and add nutes til your desired ppm/ec

p.s. i love how soluble it is, i barely have to shake the jug to dissolve it!

3 Likes