About to begin. Just a few questions about grow medium

I am a newbie. I plan on growing outside in a 5 gallon pail with drain holes. I am considering Coco coir as a medium. Thoughts on that. Do I need to fertilize sooner being there is no soil? Should I mix in Perilite? The first seed is a White Widow Auto. Has anyone used Coco Coir successfully? Any suggestions are appreciated. I live in the south there are still plenty of warm days and nights coming for the next several months.


If i grow outside i will use pro mix mixed with pig and chicken manure and some pearl lite. My hole is 2 1/2 foot diameter and about 2 feet deep or a little more i will pour blood meal and myckos a root accelerator at the bottom then at the foot mark i will pour a cup of myckos again and fill and plant then when it gets 4ft i will put about a inch of manure around it the rain storms will break it down in the south pretty good hop this helps. I’m in the Midwest and have gotten really good results on a 14 foot plant i usually get 6 or 7 pounds

This grow will be in a pot and I do not have access to those kinds of manure.

Thanks for the response.

O.k. sorry there’s soil mix recipe on here i use pro mix and peat mixed together with epsom salt and domestic lime your local grow store will have worm casting and bat shit. Then if your closer to the coast you will want a little more drainage. How big of a pot i assumed 30 gallon or better?
You can get local manure off Craigslist you want the stuff from the barn yard so it has the urine in it. It’s cheap and make s the terpins come out in the buds. Jorge Cervantes has a soil video on YouTube all about this. The owner of Humboldt seed has a video to and about pig poop. In the end it’s your call hope this helps you happy growing 🖒🖒🖒

I’m a newbie myself. I grew and harvested 3 autoflowers so far. I’ve not used Coco coir so I would wait on someone else whose used it to chime in. I do grow my autoflowers in 5 gallon fabric pots with soil. I read others autoflower journals helped me prior to starting my 1st grow. Search autoflower Coco coir in the search box and maybe get some ideas from journals.

My last two grows I have used pure coco coir. It is terrific. You never have to worry about over or under watering, because you just add nute solution every day until some runs out the bottom. You do need to put your pots (and I highly recommend cloth) on some sort of grid so the runoff isn’t reabsorbed. That contains all the excess salts so you never get a buildup. The only nutes in the coco are the ones you just put in. It really shines when you flush at the end: You just change to pHed water for the last couple of weeks and the plant burns up all the nutrients left in the plant, because none are left in the grow medium. Most of the fans turn yellow and shrivel up.

I’ve only grown clones, not seeds. I spray about every 6 hours with half-strength grow nute solution and keep the little grow cubes soaking in it. 100% success on all my clones. I would start watering new sprouts with half-strength as soon as a couple of leaves pop. That coco has NOTHING in it. It is essentially just hydroponic in solid form.

BTW, I use DynaGro Grow and Bloom and pH to 5.8 with cheap grocery store vinegar.

How soon do you start with the dynogro after planting in Coco?

Thanks for the info. Do you put nutrients in all the water you water with every day until the end and then just water. Do you PH the nutrient water to or just the water at the end?

Thanks again

I’d recommend reading up on the attributes of coco coir before you use it. One interesting aspect of coco coir is the cation exchange capacity (CEC). Essentially, certain nutrient compounds bind to coir fibers – namely calcium and magnesium. Until the cation exchange capacity is ‘filled’ or ‘saturated’ with these two important nutrients they are not available to the plants. This can result in calcium or magnesium deficiencies (you’ll often read about someone suggesting their plants have cal/mag deficiencies, actually it’s usually one or the other, not both at the same time). If you buy coco coir labeled as ‘buffered’, that means the CEC has already been ‘charged’ by the manufacturer. I still have an old compressed block that is not buffered. I mix a reduced strength nutrient solution with a cal/mag supplement added and let the coir soak in it overnight before using (drained before planting). That way I’ve buffered it myself. There are a lot of informative articles about coco coir out there. It’s worth scanning through them to better understand the medium.

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thanks for the input. Can I ask what product you are using for Calcium and magnesium supplements to soak your coco? My Coco arrived today and it is not buffered.

Thanks again

I’ve had a bottle of CALiMAGIC from General Hydroponics for quite a while. I don’t use much.

More importantly in your case, you mention you’re growing outdoors. I assume this is not in a greenhouse, right? No protection from a passing shower? I’ve only used coco coir as a medium indoors where watering and nutrient additions are controlled. Maybe some others here who use coco outdoors can chime in. The reason I mention this is because lets say you water in the morning and soon after a downpour shows up. If that happens, all or most of the nutrients you just fed your plants will be flushed out before the plants can use them. Most people, but not all of course, use coco as a passive hydroponic medium for indoor growing situations. I believe that’s why @ThcinKC posted about adding organic matter to pro mix for outdoor growing. It’s makes the medium more like soil which makes sense growing outdoors.

Also, you might need to flush your coco with plain water to leach out any salt accumulated in the coco. Coco coir is processed in tropical areas near the ocean. Different brands of coco are treated differently. Some manufacturers flush and buffer their product. Others do not. Again, I’d read up on coco a bit to make sure what you’ve planned applies coco regarding outdoor growing.

Thanks again for the info. You are correct. I will not be protected from rain completely but am somewhat, maybe 80% protected. I will be in a screened lanai under a bit of an overhang that still gets full sun all day. You have given me much good info. Thank you. I will keep reading.

I went with clones, so I used 1/2 strength DynaGro Grow from the start. With seeds, I would just use pH’ed water until the first pair of leaves showed up. But I would probably plant seeds in rooting cubes, and plant them in beer cups of coco when some roots showed on the edges of the cubes.

Yes, water every day with nutrient solution. Never use water alone until flush time at the end. If you use just water in coco, it washes all the nutes out, unlike soil. Always mix up nutes and THEN adjust pH. Flush at the end with pH’ed water, just so you don’t shock the plant.

I use tap water that has plenty of calcium and magnesium in it already to thoroughly wash and break up the compressed coco cubes. Takes care of any salt, too. Once the coco is all broken into individual strands, pour in cloth pots until you have enough to fill the pot. Then wash with a few more times that pot volume of water. of water. Let it drain: Ready to use.


If you did not still have one brick of Coco left would you switch to buffered for your next purchase?

Thanks for the info,


Yes I would. But I have so much left of the one I have now I’m going to use it until it’s gone. Really, it’s not that hard to buffer coco yourself. The other thing I think is best about better coco products available now is that most are properly pre-rinsed.

If you buy a compressed block and have hard water, the expansion process takes care of salt and buffering automatically.