Here's my take on the agricultural sulphur/ferrous sulphate and iron chelate. Agricultural or elemental sulphur will provide more acidifying power per pound of material applied, however the soil microbes have to convert it from the sulphur form to oxides of sulphur, which can then act to acidify the soil. It takes time for the acidification to work and it will occur over a period of time, you have to get the sulphur into the ground for the microbes to attack, and the effect will be a bit longer acting. The larger the sulphur particles you spread, the slower the process. Elemental sulphur is relatively cheap so is often used agriculturally. We generally use sulphur strictly as a fertilizer to replace what the crops are removing from the soil, being leached away, or tied up into mineralized compounds, plus it is relatively low volume. As a fertilizer, we often apply it at 30 lbs/acre. Another option is to use gypsum, calcium sulphate, which is commonly used to treat highly alkaline/saline soils as it is quite cheap, acidifying, and provides additional calcium. (In moister climates where soils are more acidic, they do the opposite, applying lime -- calcium carbonate-- to raise the pH). When applying gypsum, we would apply it on the order of 1000-2000 lbs/acre or more. With ferrous sulphate, you have moved up a step in cost but you are providing sulphate ions (or is it anions?) that will provide the acidifying effect, and because it is already converted to a soluble and ionic form, it will work quite quickly. At the same time, you are providing free iron that the plants can take up and the acidifying effect of the sulphate slows the process of tying the iron up in the soil. Many soils, particularly in alkaline areas, have plenty of iron, but it is tied up in the soil and unavailable to plants, and that is the situation here. We have a lot of red soils, the red coming from oxidized iron (rust). There is no deficiency of iron but it is mineralized and unavailable. Combine that with a pH of around 8 or higher and there are a lot of plants that will die of iron deficiency. Conifers, golden willows (lost a row of them in the cemetery to that, and nearly lost the spruce trees), petunias, raspberries, and even kentucky blue grass where the lawn is only sprinkler irrigated, for example. With iron chelate, you have a form of iron that is more available to plants, however it is relatively much more expensive. The chelate can be absorbed into the leaves if used as a foliar spray, though too strong a solution will burn. Because it can be pretty well directly absorbed by the plants, it can have an almost immediate effect on new growth. I've seen it recommended to water the ground with the iron chelate, but I think it tends to get tied up in the alkaline soil fairly quickly (I think the chelate breaks down fairly quickly, then the high pH ties up the iron again, and you need large quantities which become quite expensive. I had always had recommendations from the extension service to use iron chelate for iron deficiency, but later I was advised to use the ferrous sulphate by a professor for the combined free iron/acidifying properties. When I used the iron chelate, I never had much in the way of results unless I sprayed weekly at least, and that just doesn't happen with me. With the ferrous sulphate, I could spread it once and see lasting effects for anywhere from the remainder of the summer to several years. Part of my lawn is watered with a sprinkler using well water which is very high in lime. Gradually it turns yellow and thin with iron chlorosis. Fertilizing with nitrogen had no effect. Add some ferrous sulphate and in a week it was turning green, growing like it was badly overfertilized, and the stand thickens up. One year my supplier stopped carrying the ferrous sulphate but had ferrous gluconate and said it was much easier to use and worked the same--so I wondered but tried it. Think I still have most of the bag. It showed no effect on the plants, smelled like molasses and had no irritating dust so I found a new supplier for the ferrous sulphate (I'm not going to apply it if I don't get results). I don't fully remember my chemistry from school, acids/bases, oxidizers/reducers, strong vs. weak acids & bases & the chemical reactions that take place when these chemicals are placed in solution and I'm sure there are those out there that can more than adequately cover the subject (not that I'd want to learn it all over again, though!) I mainly try to cover some of the principles and describe what has worked from experience. Plus, I've never tried to grow blueberries as trying to provide an acid environment in my soil seems like too high a maintenance. Overall, what is being dealt with here is that in drier climates, the soils tend to have a large reservoir of lime and an alkaline pH. Acid loving plants may not need acid to live, however they consume quantities of minerals which are mineralized and unavailable at high pH, but become readily available at lower pH and blueberries have adapted to soils where these minerals are readily available. Trying to lower the pH of the soil to create an acid one suitable for blueberries is very hard, because to make the soil acid you have to essentially eliminate the alkaline lime in the soil, and it will take tons of amendments to do that. To compensate, you remove the soil, replace it with organic matter which is naturally acidic, then work to counteract the ongoing process of your climate and geology from turning the new acidic, organic soil back into an alkaline, mineralized soil and add a few of the more important nutrients the plants need so that they are readily available, even if the pH is a little higher than the plant desires. One last caveat--in acidic soils, NEVER add ferrous sulphate for an iron deficiency. You don't need more acid (unless you actually want a more acidic soil). Use iron chelate or the ferrous gluconate. Sorry this is much too long, but hopefully it explains the basis of my thoughts so you can judge for yourselves what is best in your situation.

There are plenty of great reasons to plant opuntia. The fruit is great, it has gotten out of vogue, but in th 40-50’s it was highly prized and sold for a nice price for growers. The pads are also good to eat but take a little work. Luther Burbank was so taken with the plant, its hardiness, rapid growth, very low cost to grow and high nutritional value, he spent may years planting it and trying to develop a thornless variety. He got close but never succeeded. He envisioned this plant to end world hunger. Besides the beautiful flowers and colorful fruit, the plant makes an incredible barrier for keeping people out. It is better than a fence when grown in. You are not going to climb this fence. When planted along an existing chainlink fence, only small creaturs will be able to pass. When thick it is also a great noise barrier. Any product that is made for weed control in beds of iceplant will not harm opuntia. Roundup is not recommend for use to kill cactus, but it will in a strong solution. Over spray of a solution of .8 to 1.6, which is recommended for almost all weeds would need to be actually applied to the cactus, wetting it all, to cause any severe damage, over spray at that level will have no effect. But when you have an established cacti bed, spray a pre-emergent, then you will only need to spot treat later for weeds. David

I'd be hesitant to spray roundup on the lawn since the grass may not be totally dormant. Since weeds are primarily broad leaf why not spray a broaf leaf weed killer on them? Perhaps that is what you used already. It may take a few days to a couple of weeks for them to die, but I find that it works well. The big ones you can pull up. Try to not let them go to seed. Spray very carefully with the sprayer set to emit large droplets and not a fine spray so it won't drift over to any shrubs you may have. You may need to apply a pre-emergent weed killer to keep seeds that are still in the soil from sprouting. There are organic and chemical kinds you can use. It will take diligence to keep the weeds down until the lawn gets thick. Before you get the weedy lawn beat you'll be pulling and spot treating so many weeds you will see them in your sleep! Most of us have been down that trail before we had a weed free, or nearly weed free lawn.

The glyphosate products might kill actively growing weeds, and any other plant it contacts since it is a plant killer. Do not ever accept any advice about gardening from anyone employed by one of the big box stores because they have certain materials the store wants sold that they push, good, bad, or indifferent advice, but I have found very few that really know what they are talking about. Contact your local office of the Texas A & M USDA Cooperative Extension Service and ask for their help in 1)identifying which "weeds" you have, and 2) what is the most appropriate material, or method, to use to control them. This link, about natural lawn care is from Ohio State University but most of what is there can also be applied in Texas. Here is a link that might be useful: Natural Lawn Care