Reader's Questions, Part I

So to the questions! I might break this into two posts so it doesn't become a novella, but we'll see. And thanks to everyone who e-mailed me questions. I'm not posting names, etc., here (because technically, I didn't get everyone's permission to post these) but if you see a question you wrote, feel free to bask in my gratitude.

#1: Hi Jon In the photo below should I be concerned about anything and if so what is it and how do I treat?

Answer: This is a condition called catfacing. It's actually a malformation of the blossom caused by incomplete flower development. This, in turn, is typically caused by cold weather or cloudy weather that messes with the flowers as they first set fruit. Heirloom tomatoes are somewhat more susceptible to catfacing than some of the newer hybrids, which have been bred for uniformity of shape. For the most part, catfacing is a harmless, but strange-looking and even ugly condition. It does become a problem, however, when the skin splits and allows pinworms an entry point.

#2: I was reading some of your articles on your index but could not find if fertilizing should stop at a certain time prior to harvest or if I can continue to fertilize my tomato plants right up to and through completion of harvest.

Answer: Good question! Most people are growing indeterminate tomatoes (vines) that produce fruit over a period of time until the vine dies or the heat sets in and kills it. (Technically, tomatoes are perennials—a single well-managed vine can produce for nine months or more.) So yes, you can keep these plants going longer and producing longer by continuing to fertilize throughout the plant's entire life, even as you're harvesting fruit. You can also extend the harvest by removing brown and dead leaves and keeping the plant in good condition. Production will move from the bottom of the vine to the top of the vine. Of course, a major limiting factor for most people is space—who has room for a 12-foot vine?—so we top our plants. But we can still feed throughout to give them a boost. For indeterminate tomatoes, keep feeding up through harvest.

#3: A leaf-curling twofer ...

Is it a sign that my tomato plants are not getting enough water if the leaves are curling? AND

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.

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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.