It's pine bark, but it's hard to say by the picture if the size of the bark is appropriate. It looks like it's quite large. If you read the link Jodi left for you upthread, you probably realize that particle size and distribution is very important to how a container soil performs. Here is something I wrote to illustrate the importance of particle size/distribution: Obviously, I think the grower's soil choice when establishing a planting for the long term is the most important decision he/she will make. There is no question that the roots are the heart of the plant, and plant vitality is inextricably linked in a hard lock-up with root vitality. In order to get the best from your plants, you absolutely must have happy roots. If you start with a water-retentive medium, you cannot improve it's aeration or drainage characteristics by adding larger particulates. Sand, perlite, Turface, calcined DE ...... none of them will work. To visualize why sand and perlite can't change drainage/aeration, think of how well a pot full of BBs would drain (perlite), then think of how poorly a pot full of pudding would drain (bagged soil). Even mixing the pudding and perlite/BBs together 1:1 in a third pot yields a mix that retains the drainage characteristics and PWT height of the pudding. It's only after the perlite become the largest fraction of the mix (60-75%) that drainage & PWT height begins to improve. At that point, you're growing in perlite amended with a little potting soil. You cannot add coarse material to fine material and improve drainage or the ht of the PWT. Use the same example as above & replace the pudding with play sand or peat moss - same results. The benefit in adding perlite to heavy soils doesn't come from the fact that they drain better. The fine peat or pudding particles simply 'fill in' around the perlite, so drainage & the ht of the PWT remains the same. All perlite does in heavy soils is occupy space that would otherwise be full of water. Perlite simply reduces the amount of water a soil is capable of holding because it is not internally porous. IOW - all it does is take up space. If you want to profit from a soil that offers superior drainage and aeration, you need to build it into the soil from the start, by ensuring that the soil is primarily comprised of particles much larger than those in peat/compost/coir, which is why the recipes I suggest as starting points all direct readers to START with the foremost fraction of the soil being large particles, to ensure excellent aeration. From there, if you choose, you can add an appropriate volume of finer particles to increase water retention. You do not have that option with a soil that is already extremely water-retentive right out of the bag. I fully understand that many are happy with the results they get when using commercially prepared soils, and I'm not trying to get anyone to change anything. My intent is to make sure that those who are having trouble with issues related to soil, understand why the issues occur, that there are options, and what they are. Many use their current potting soils (like MG or used soils as a smaller fraction of a new media they put together specifically to improve drainage & aeration, so yes - you CAN use some of the soil you have as a fraction of a new soil, but keep in mind that you aren't going to rid yourself of the drainage/aeration and high PWT issues problems unless your soil is weighted heavily toward larger particles than your current soil is currently comprised of. When you add a little extra perlite and/or pine bark to a peat-based soil, you don't change the drainage characteristics, the height of the PWT, or aeration. You DO decrease the total volume of water the soil CAN hold, and that IS a plus, but that's about all you really accomplish. Add a LOT of (appropriate size) bark and perlite = job done. The physics of how water behaves in container soils doesn't change because someone might assure you it does. As surely as the cow is barred from jumping over the moon by the law of gravity, soils are bound by physical laws to exhibit rather specific and predictable characteristics based on their particle size and distribution (enter the pudding analogy into evidence). If you choose not to go with a soil that has a considerable fraction of larger particles, there are ways to help you deal with excess water retention when it occurs. There is a lot of good information about dealing with water retention if you follow the embedded link. When you get to where you're deciding about how you want to proceed with your soil, we can talk more specifically about tailoring a plan that best supports your methodology. Take care. Al

Not for long, and the practice negates one of the important reasons the gritty mix is so effective - the superior drainage built into the soil helps prevent the build-up of soluble salts. Also, the effluent soon has little similarity to the fertilizer solution you originally applied, and you can expect (high) pH to quickly become an issue. There was a Dr that hung around for a little while, who was growing dahlias or zinnias (maybe it was something else) and was trying to recycle the effluent. We had the same discussion you and I are having, and he eventually determined the things I'm sharing with you were indeed the source of his issues. Al

If you begin watering your plants with non-toxic physiological levels of nutrients, then the levels only become "toxic" (i.e., concentrated) because of water loss through the mechanisms of transpiration and evaporation and (minimally) by plant metabolism. So if care is exercized to return the amount of water to its original volume (by the addition of salt-free water to the drainage) then the concentrations of the salts in the drainage will return approximately to their original levels. Of course, since plants utilize the nutrients at rates peculiar to each nutrient, then with time the concentrations of individual nutrients and the ratios of nutients to each other will become altered beyond acceptable range. Since it's beyond the capability of most of us to re-adjust each nutrient level individually, it's probably simplest at some point (weekly? monthly?) depending on your watering schedule, to discard the drainage water entirely and begin again with a fresh nutrient solution. This is the rationale that is used in so-called "ebb-and-flow" hydroponic systems.

I might wonder about bad bacterial growth in the reused water, if the water sits in the pan for a while. Soil is rich in bacteria, but the soil biology tends to suppress the bad stuff. But I guess this is no different than just having a puddle of water near a garden. Of course, a lot of your Powerfeed is going to be collecting in that drain water, so as you add more Powerfeed to the top as you reuse that water, the concentration of it is going to steadily increase with evaporation. That is, there is no runoff or loss into the depths of a bed. At some point, it may reach an unfriendly concentration. The NPK of Powerfeed is significant, so you could easily end up overdosing on that. If you use that water, I'd stop using Powerfeed for a while. The NPK of seasol is minimal, so it seems less likely that you'll OD on that.