WOW - that doesn't seem like much water. Only relative to the amount you've been using. Question: Why do you feel obgliated to water so much? You have to let it dry out. The number one cause of death of house plants is over watering. It is also common with vegetable gardens. Over watering not only suffocates the roots, it encourages all types of fungus and disease problems. You're stressing your plants and making them weak because they literally can't breathe. People think they only breathe thru the top foliage, but they breathe thru the roots equally if not more. Think of how your skin looks and feels after you sit in a bathtub full of water too long. In your case, after your moisture meter test, here is what I recommend to you housemouse: Don't water for a week. Yes, an entire 7 full days of no watering by housemouse. Is it possible? it came out at 3-4 (on a 0-10 scale) at a depth of about 3". The deeper I went, the more moisture there was. This is why plants can survive in drought. Especially native plants whose roots can go down 16 feet. But if you water all the time then the roots don't go down and area spreading out near the surface making them much more susceptible to fluctuation and less stable in the long run housemouse, I don't think you should be so worried about the pH as much as you should be worrying about the N-P-K levels of your soil. But if the pH is varying so much perhaps your soil was not mixed well. Where are you located? What county and state? Then water deeply no more than once a day, preferably in the morning, on days when it is really hot and no more than every other day or even every 2 days the rest of the time. Still too much, especially with the recommendation to deep water that often. You should only deep water once or twice a week. If done properly, there will be plenty of moisture available to the roots even if the top of the soil is dry. Oh, and the plants sitting in the water in the greenhouse...please dump out the excess water. Seedlings should never be left sitting in standing water. They can't get air (just as important as water) and it rots the roots. Let them drink their fill and then dump the water that isn't taken up within the first few minutes. Yes. 100% agree. In fact, what are the seedlings? housemouse, How thick of a layer is that wood mulch? You wrote: " haven't added any fertilizer yet - maybe that's my problem?" Your plants look like they need fertilizer. Compost is fertilizer. The industry has everyone believing fertilizer is the answer to everything when the reality is that concentrated fertilizers cause far more harm than good more often than you think. Use compost which is nature's fertilizer and nature has been doing it for thousands of years. You can't burn your plants, it releases at the proper rate for the root systems, you can't go wrong so long as you use a blend of compost created from at least five different sources.

I live in the north-central area of the USofA, and am a huge zinnia lover. May I suggest buying lilliput zinnia seed, or dwarf zinnia seed. I start my zinnia's in Jiffy 7's about 8 weeks before last frost date. The dwarf zinnias are slow to germinate, some of the best colours are the slowest to germinate, so I take that into consideration. When planting out time comes I crowd them in my plantings, and have spectacular results. It is as if they support each other while stretchinig out for more sunlight. Zinnias do need fertile soil and full sun, but the rewards are great. Mine always are lanky, but crowded together they produce long stemmed flowers. I also plant some of the California Giant Zinnia's, and they truly are giants of my garden. Fortunately the seed is available by the ounce or part of ounce at the garden center near me. A fungicide of natural or chemical nature is almost always needed to keep the plants healthy. Like mentioned by others..topping off and deadheading is worth the effort. Yes, zinnias are a great cut flower, and last in bouquets a long time.

I have a similar problem with a plumeria that has sun damage. The tree was doing so well this summer. It grew very well and bloomed all summer long. When the nights started to get chilly we decided to put in our small greenhouse. We neglected to open the top of the greenhouse during the day time hours and the warm sunlight filtering through the top of the greenhouse burned our plumerias leaves. The base of the tree remains firm and solid with no sign of sponginess or rot. Does anyone have any suggestions as to what to do with the stems and leaves that have been burned and are getting spongy? I have pictures but I am not sure as to how to post them.

Austin has some pockets of really truly cr@ppy soil, and some good stuff. Soil tests are our friends. Learning about the different solutions for amendment. I have heard that some people with red death clay have brought in some composted HARDWOOD native mulch and tilled 6" in and then not done anything with it for a year and let it rot. Others have loaded on 6 inches of compost and let the bugs cary it into the dirt. Sounds almost to good to be true. I used to live on clay. Not red death but a river cut bank with round river rock in it. Everytime I was out their with a shovel, I had compost from the Natural gardener to work into it. It got to be glorious dirt. I could grow everything. I thought I was a good gardener till I moved to 30 miles west of Austin on a high limestone hill with caliche and marl with mostly not much topsoil in the area around the house.. Many natives need to have the clay worked into loam by the bunch grass roots. that have broken it down. Find native grasses that want to break down the clay. Find a way to create structure in the clay. Gypsum, expanded shale, compost . Be aware the adding sand or decomposed granite has to be done in conjunction with more than equal amounts of mulch. One has to add at least 50% sand to have the clay not go back to cement. Research research research. I live on caliche now and I created raised beds in some areas where I grow vegetables because it was easier and immediate. I recommend compost tea. Geo Growers and the Natural Gardener for soil products. If you have a recurring bug or decease problem, step back and let the soil heal itself. I had to step back from squash because of the squash bug. I am giving my whole garden a rest this year and growing green manure. The arugala, leeks, kale and chard have not heard that I am not growing anything this winter.. When it is hot, I start vegetables in pots in the shade.