Peat Based Soilless

pro-mix, worm castings,perlite

thundergro
jack's classic
roots hpk bat guano
strapped

Nice. A lot of folks use castings in their blend. What % of your mix is castings? I read that anything over 10% can result in reduced air retention-- not sure if that's true, though.

WHat exactly does the dolomite lime do? First time I used promix bx I had some sickness in the beginning with transplanted clones, but gro big brought them back around. Why hydro nutes over regular gro big? i guess I don't know as much about growing with promix as I thought. Even though I was very successful last time could someone with some more experience give me a few pointers seeing as I just started my next grow? Germinating five feminized master kush (nirvana) and transplanting four into a 3.5 x 2.5 ft scrog setup with four five gallon pots. RIght now I have a mix of 3 parts promix bx and 1 part perlite. I have gro big but don't think it's hydro specific. T5 for veg and then moving to the flower room under the thousand hps. Any tips on the medium and specifically nutrients for the seedling and veg stage much appreciated.

Originally Posted by 808dank

WHat exactly does the dolomite lime do?

Thanks for the questions, Dank. I like many growers, I have gravitated to my method by trial and error, and it's good to review the 'whys'.

Regarding dolomite lime, it serves two purposes. First, it acts as a buffer in the soilless medium, continually moving the ph of the medium towards 7, and speeds the decomposition of any organics in the medium. This actually saved my ass on this grow. I got a false read on my ph, and accidentally fertilized a couple of my plants with a solution at about ph4-- yikes! I didn't pick up on the problem until the next day and flushed the two plants. Some damage was done (a couple leaves got a singed), but I believe the damage was greatly reduced due to the presence of the dolomite lime.

Dolomite also acts as a longer term source of magnesium and calcium. It isn’t a big source, but when combined with my home well water, I don’t need to any cal/mag to my nutes.

Some folks claim that dolomite lime is not helpful until it has 'cooked' in the soil for a while. I don't agree with this, and here is an article based on research that shows how the buffering qualities of dolomite lime happen immediately, and calcium and magnesium are available within a few weeks.

http://www.greenhousegrower.com/arti...-and-magnesium

Originally Posted by 808dank

Why hydro nutes over regular gro big?

I have read a lot of folks say that there is not much of a difference between the hydro and soil versions of Grow Big—they are wrong. Other than additional K in the hydro version, the NPK ratios are very similar (hydro 3-2-6 and Soil 6-4-4 ). BUT the ingredients in each product are very different, and are tailored to address each medium.

Here is a table of the major ingredients of the two products, and a ranking of where each ingredient is in each fertilizer.

Ingredient	Rank Soil Based	Rank Hydro Based
Ammonium Sulfate	1	-
Urea	2	-
Potassium Nitrate	4	1
Magnesium Nitrate	-	2
Blood Meal	3	-
Potassium Sulfate	5	-
Potassium Phosphate	-	3
Ammonium Phosphate	-	4
Ammonium Nitrate	-	5
Calcium Nitrate	-	6
Earthworm Castings	6	7
Norwegian Kelp	7	8

Note that the soil based formula is high in ammonia based nitrogen sources. marijuana prefers to take up nitrogen through nitrates. Ammonia must be converted to nitrites, and then nitrates before being taken up as effectively. That’s fine for soil, where you want to have a whole bunch of biotic activity taking place, but in a hydro system (including soilless) you want the nitrogen to be more immediately available.

Originally Posted by 808dank

Germinating five feminized master kush (nirvana) and transplanting four into a 3.5 x 2.5 ft scrog setup with four five gallon pots. RIght now I have a mix of 3 parts promix bx and 1 part perlite. I have gro big but don't think it's hydro specific. T5 for veg and then moving to the flower room under the thousand hps. Any tips on the medium and specifically nutrients for the seedling and veg stage much appreciated.

Post some pics here, if you would like-- I'd love to see your grow.

You have a lot of light for a 3.5 x 2.5 ft scrog setup. I like to grow a 3x3 scrog with 400w. You are pushing your plants harder, so you might need to run nutes differently than I do. Basically, I run 1.5 tsp/gal Grow Big for veg, and build up to adding 1.5 tsp/gal Tiger Bloom by the 3rd week of flower. I also put in 1 Tbs/gal of Big Bloom every other water, and some Silica if the plants 'ask' for it. I feed to 25% run-off and flush every 3rd week.

Thanks Nitegazer for the detailed reply. I was browsing the forums after my initial panic when I saw promix, soilless, and hydro all being used synonymously and was able to calm my nerves. I was reading about the BX already having buffers mixed in, including dolomite lime. I know the PH level is typically lower than 7 and plan to just monitor the PH levels closely to make sure I don't have any issues, and if need be I can bring it up and make adjustments.

I found some interesting articles on the benefit of the micorriza and seems a lot of people are too quick to shoot it down, claiming things like it's instantly killed in light, or that any fertilizers kill it off and ruin the cost benefit ratio. Seemed to work just fine for me with my last grow...I got excellent root growth and the plants were healthy and hearty. Sounds like a flush or two throughout the grow will help to control salt buildup.

I'll post some pics eventually once I get the chance to snap a few. The grow I'm doing is actually a perpetual setup, and in the flowering room I'm going to have two separate scrog boxes, both 3.5 x 2.5, giving me an actual area of 3.5 x 5ft under the 1000w. Each individual "box" has four plants, clones eventually, and starts off under the T5 for veg, then cycles into the flowering room as the third box is just harvested. (Or so goes the plan) The boxes are on wheels for ease of access and can easily be moved in and out of the room for any maintenance, watering, etc.. Any height issues I have when I move one box over and introduce the new box (just starting flowering as opposed to four weeks in) should be easily manageable by just raising the box up to the level of the more mature plants, giving everyone the light they need to stay happy.

Again thanks for the info...really helpful. I'll keep you updated on how things go and get some pictures up soon.

Hey, this thread is a little old but I figured I'd give it a shot. So I'm a month into flowering with my first cycle now, and two days into flowering with the first batch of matured clones.

The four plant scrog that is 30 days into flowering has some sort of deficiency issue (or possible burn??) going on with all 4 plants. We realized our PH meter is junk and have since decided not to rely on the readings. Here's the feeding schedule...

Medium: Pro Mix BX
5 gal pots
master kush scrog
veg: 2tsp gro big / gallon
2drps Superthrive
1/2-1 tsp PH up (water had low PH levels, around 5.3 after adding nutes, so we raised the PH to 6.8 to correct during veg and plants bounced back from the initial yellowing and necrosis issues)

Flowering: 2.5 tsp tiger bloom
1/4 tsp open sesame
4 tsp PH up
1 drop superthrive

Plants initially looked healthy. Upon introduction of the first full strength nutrient mixture for flowering (3.5tsp/gal tiger bloom, 3tsp PH up, 1 drop superthrive) they still looked healthy, no signs of burn or deficiency. They were watered again on 9/19 with the same nutrient mixture plus 1/4 tsp/gal of open sesame. Two days later the leaf tips were turning brown and dying so the plants were flushed on the next watering.

on 9/25 they were watered with 1/2 tsp open sesame per gallon, 3 tsp PH up, and 1 drop superthrive. On the 28th they again got full strength with 3tsp tiger bloom. More signs of burn or deficiency progressed, so on the next watering the open sesame went from 1/2tsp /gal down to 1/4tsp / gal and half the PH up. On the 4th the plants were again watered with less nutrients, this time 1.5tsp tiger bloom, 1.5 tsp PH up and 1 drop superthrive.

The plants have dead brown/yellow leaf tips that are seeming to curl up rather then down. The blades on fan leaves are all yellow at the tip but not curling up or twisting like Mg deficiency. The thought initially was that chemical burn was the problem, and the plants were flushed with straight water and then followed up with a lower strength nutrient mixture. After things kept progressing the thoughts turned to PH problems and possible nutrient lockout.

During the end of Veg and for the first 3 weeks of flowering, PH up was added to each mixture to bring it up to 6.8. This was because the runoff was down at about 5.1-5.2. When our PH meter became junk and we decided not to trust it was when we realized we didn't know what the actual PH of the water was that we had been giving them. If you assume our starting level is close to 7 (just plain water), is 3 tsp/gal of PH up too high when mixed with 3tsp tiger bloom/gallon? I feel like the plants have just been getting a guestimate of PH adjusted water, which might be too high leading to nutrient lockout. Should our target PH range of the water really be in the 5.7-6.0 range for a peat based medium? Is it ok that the runoff reads lower?

Lots of information to take in, I know. Thought you might be interested in sharing your opinion nitegazer. From what you wrote about your feeding schedule it sounds like you don't use any PH up? So I would guess your nutrient mixed water (if it started at 7) would be down in the 5.8 range?

Again the deficiency is on all the leaves except some of the smaller new growth around the buds. dead leaf tips curling up and the tips of the blades are yellow and dead. Any thoughts appreciated, mainly on the diagnosing between chemical burn or PH balance being off. Buds are still looking healthy and the second round of 4 has just started flowering and is healthy. Hope things only improve from one batch to the next.

mahalo

This year my outdoor growing medium and nutrients were...

7.6 cubic feet Sunshine #4
3 cubic feet Bcuzz coco
2 cubic feet earthworm castings
1 cubic foot perlite
3 pounds Dr. Earth bat guano (10-3-1)
2 cups Spinosad plus pellets (to help prevent caterpillars)

Veg
Sensi Grow
Liquid Karma
Great White
Superthrive

Bloom
Sensi Bloom
Bud Candy
Sensizym
Big Bud (powder)
Liquid Karma

Fresh water and nutrient pH @ 6.2