I have a mystery. Yesterday, I noticed the leaves on the upper half of my plant are starting to curl into burritos. I have changed nothing. I even brought the plant in when we had a very cold night a week ago. Can you diagnose for me?
Answer: Ah, leaf curl. It drives me crazy too, and I've spent untold hours trying to figure out what causes leaf curl and how to stop it. I ended up finding a lot of conflicting information and very few solid answers. In the end, though, leaf curl is a generally harmless condition and it won't affect your fruit set or harvest. As long as leaf curl is the only thing going wrong, no big deal. If it's accompanied by yellow leaves, brown spots, black spots, stunted or frizzy growth, or any other symptoms, that's a different ballgame and there's a problem.
#4: My local nursery sells their own mix of potting soil that sounds like what you get.
I don't have a list of the exact ingredient but from what I remember it contains
peat, fertilzer, dolomite, perlite. It comes in 2 cu/ft bags. Would this be good in my pots? Would you use only this or mix in something like Black Kow? How many bags are needed for a 25 gal. container?
Answer: At first glance, it sounds like a pretty standard potting mix and that's a good thing (with one caveat). The soil mix I typically use includes these same basic ingredients. But let me back up a few steps. A good potting soil mix has a few characteristics we care about: structure, water-holding capacity, nutrient-holding capacity, and an acceptable pH. Thus, a very basic mix might just contain peat (water and nutrient holding), perlite (structure, to allow drainage), and dolomite (a pH balancer). In higher end soils, you might also see pine bark fines (more structure). Anything after that is fertilizer or bonus ingredients, along with wetting agents to keep the soil moist in the bag. In general, I don't buy soil that has fertilizer already added to it—it's typically a balanced fertilizer and not geared for vegetable growth. Instead, I add my own fertilizer elements, like blood meal, bone meal and composted cow manure (Black Kow) to enrich the soil. I never recommend using soils with water retention crystals for tomatoes. So in answer, the question of adding organic fertilizer elements, like Black Kow, is a personal one. Personally, I do. BUT also remember, compost is heavy and reduces the soil's structure. So if you add stuff like compost to bagged soil, throw in 1 part perlite for every 2 parts of your compost addition. Keep the soil light, fluffy, airy, and able to drain quickly. You can always feed later in the season, but you can never correct for heavy, soggy soil.
Lastly, that's a good question about conversion rates, so here it is. There are 7.5 gallons in a cubic foot. So I use 25-gallon containers, which means it takes about 3 cubic feet of soil to fill them up and leave a little space at the rim. This can get pricey if you're buying custom mixes, so I tend to buy all my own bulk ingredients and usually spend about $100 in soil ingredients each season.
Whew. OK, so that's it for today. More coming, and if you have any questions, send 'em over and I'll add it to the list.