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

You can try pickling vinegar (this kind of vinegar is higher in acid so works better than regular vinegar), works for a lot of weeds but i'm not positive on grass.

.. If you feel compelled to pasteurize all your materials before composting, have at it. If you want to pasteurize after the fact then I think you are throwing away something of value. The folks that grow mushrooms pasteurize everything before grow their mushrooms. If you take all that stuff after they are done with it, you will get all the microbes floating in the air to start the decomposition process over again and it will continue to compost but with a delayed action. The hot composting process will get you 140 F to 160 F and will kill off most, if not all, the things you may be worried about. Boiling water is 212 F or 100 C and will kill everything. Once everything is killed (pasteurized) it will just take time for all those happy microbes that are ever present to settle in again and digest the result. Yeah, boiling water will kill the seeds. It will kill everything else too and then you have to wait for life to move back in. Keep weeding and over time you will have less weeding to do. You will never get rid of all weeding entirely. to sense ..

Those are wild violets. There are a couple different ways to kill them depending on how bad of an infestation you have. If you have a lot of them triclopyr is what you need to use. Ortho Weed-B-Gon Clover, Chickweed and Oxalis killer is the stuff to get. I prefer the concentrate which you mix up in a pump up sprayer. I use 2 ounces per gallon of water and be sure to mix in a non ionic surfactant to make it stick. You will need several applications about 10 to 14 days apart. Keep spraying them until they are brown and dead. This time of year you will have to be careful as you might get some turf damage if the temps are above 85 degrees. On another note, this is for cool season grasses only. This stuff will kill bermuda. Another method that probably works best if you don't have a lot of wild violets to deal with is Glyphosate (aka RoundUp). Pour a little straight glyphosate in a cup and add some non ionic surfactant (baby shampoo or liquid dish detergent will work too) and using a small hobby type paint brush paint each leaf with glyphosate. This method only takes one application to kill them plus it really doesn't matter how hot the temps are. Once they're gone you will still need to keep an eye out for new plants popping up. As soon as you see a new one hit it with the glyphosate. They are extremely hard to get rid of but with some vigilance you should be able to reach a point where they are easily manageable.