Help me grow some salsa!
May 20, 2008 10:31 AM   Subscribe

Growing a few green chile plants in the hot desert. Any tips or tricks?

We've planted a small garden in pots in our backyard. We have three Big Jim green chile plants, two Roma tomato plants, and two tomatillo plants. We live in Tucson, AZ, so it gets incredibly hot and dry out here. Earlier efforts to grow plants were met with failure, but this was always plants that were in the ground. In a pot we're able to control the soil conditions much better and also place the plants where we want.

We have the plants along an east wall of the house. They're in full sun until about noon. It's just too hot to leave them in full sun all day; when it gets to be 105+ with 10 percent humidity every day, the sun just destroys plants, in our experience. Full sun also means that later in the day the water in the soil gets hot enough to do serious damage to the plants according to plant nursery workers we've talked to. So for this climate, full sun all the time is not a good idea. Since the soil in these pots is not new, and we presume somewhat stripped of nutrients, we're giving the plants Miracle Gro once a week.

So far the plants are doing well. The chile and tomatillo plants are flowering, and two decent sized chiles are already growing. The tomato plants aren't flowering yet but are growing nicely. Here's my questions:

1. Any idea what kind of yield we can expect if we do well?
2. Should I start shading the plants in a few weeks, when it's clearing 100 degrees before 10am?
3. What should I do for plant feeding? (Are coffee grounds good for vegetable plants? That's something that seems to be doing wonders for the sagebush out front.)

If these first few plants go well, I'd like to really expand and start growing more. The idea of being able to walk out the back door and nab the ingredients to make salsa on a whim is something that would make me extremely content. Any other tips are appreciated!
posted by azpenguin to Home & Garden (10 answers total)
Some fertilizers cause some plants to grow more stems and leaves and they never get around to flowering or fruiting, so it's okay to fertilize at first but lay off after the plants look like they're getting off to a good start.

Peppers shouldn't be over watered; you get more heat and flavor out of thirsty chiles.
posted by mds35 at 10:42 AM on May 20, 2008

In a pot we're able to control the soil conditions much better and also place the plants where we want.

Eh -- this is only true if you're incredibly vigilant. The soil in your pots will dry out much, much quicker than well-watered earth, even if the weather surrounding that earth is really hot. The soil temps will be a lot higher in pots, too, and this can have an adverse effect on your plants' growth.

1. Any idea what kind of yield we can expect if we do well?

What are your nighttime temps? That'll be the biggest factor. Peppers don't like to set fruit if the night temperatures are above 70. Tomatoes feel the same way about the nighttime, and are balky when daytime temps are above 90-95 (sources vary on that one).

2. Should I start shading the plants in a few weeks, when it's clearing 100 degrees before 10am?

Anything you can do to keep the temps down below 95 is a good thing. Try shade cloth that lets the, you know, "sun vitamins"** in, but keeps heat out. Also make sure you're not creating a greenhouse in the process.

[** Not a real term. I am undercaffeinated.]

3. What should I do for plant feeding? (Are coffee grounds good for vegetable plants? That's something that seems to be doing wonders for the sagebush out front.)

Once the plants are healthy and established, you don't want to feed them. Excess nitrogen will make the plant want to grow, grow, grow -- not fruit, fruit, fruit.

Don't use plain coffee grounds -- especially in pots. It'll just release a bunch of acidity into the soil, and in such a small amount of soil that could burn your plants' roots. You can find plant foods formulated specifically for tomatoes. I'd go that route and feed only once or twice (for both the tomatoes and the peppers) and then, no more food.

Good luck! (I think you might need it.)
posted by mudpuppie at 12:03 PM on May 20, 2008

Addendum: I understand your past efforts to grow in the ground haven't been very successful, but I think that done right, it SHOULD be more successful. The key is long, deep, not-frequent waterings that encourage the roots of the plants to go deeper than they normally would. (Say, one hour, once a week, with a soaker hose.)

Deep roots can tap into water not available at the soil's surface, and that keeps the plants happy and healthy during the heat of the summer.

I'm sure your container garden is gorgeous, but it's not really the best way to grow tomatoes/peppers.

But again, good luck!
posted by mudpuppie at 12:06 PM on May 20, 2008

All the advice above is good; it's pretty much what I came here to say... MiraclGro fertilizer is lousy, however. Plants in decent soil don't need that much fertilizer, and that one is particularly crappy, since it leaches nutirents easily (especially from pots) and tends to build up excess salts in soil.
posted by oneirodynia at 1:46 PM on May 20, 2008

Sorry to be so brief- I'm actually on my way to a client's garden right now- just wanted to add that too much fertilizer, particularly synthetic fertilizer, is bad because it encourages soft, fast growth that bugs, fungi, and other pests and pathogens love. Slower release organic fertilizer doesn't have this issue.
posted by oneirodynia at 1:52 PM on May 20, 2008 [1 favorite]

I haven't been able to keep a tomato plant alive long enough yet to see a tomato out here in Phoenix, but I can answer your coffee grounds question. The soil and water in southern AZ are highly salty and alkaline (the pH can be over 8 and the calcium hardness over 500 ppm coming from the tap). Coffee grounds are good to mix in because they're acidic, and will move the soil towards a neutral pH over time. The salt unfortunately is going to slowly build up in the soil every time you water the plant. Once every month or two you can drench the plant, letting plenty of water run out the bottom of the pot. This will help wash some of the salts out.
posted by TungstenChef at 4:50 PM on May 20, 2008

Oops, I didn't read mudpuppie's post close enough, he/she is probably right that you won't need coffee grounds in potting soil. Your water will slowly turn the soil alkaline, but tomatoes and peppers will fruit before it's enough to be a problem. If you're reusing potting soil or growing ornamentals with longer lives in pots the plants will appreciate some acidity and flushing out of salt though.
posted by TungstenChef at 4:58 PM on May 20, 2008

azpenguin, have you called your county extension office? They might have some specific tips, too.

Also, poke around the website. It's not quite as hot in Las Cruces as Phoenix but they know a LOT about growing green chile. My aunt started grad school there specifically working with chile plants.
posted by sugarfish at 6:25 PM on May 20, 2008

Eek! Stop fertilizing!

Supplemental feedings are only recommended about every six weeks - or for tomatoes, three times total. And that's if you're using easy organic stuff like plain old compost. Miracle Gro - and once a week - will kill your plants in a hurry!

Chemical fertilizer not only makes the soil very salty and can burn the plants, but doesn't contain all the micronutrients, beneficial bacteria, and minerals that all plants truly need (it's like trying to live on a diet of Doritos and thinking you've got your dairy and your grain food groups covered). Instead, buy a bag of compost and heap that around your plants. Then every time you water them they get a nice gentle root-bath of healthy compost tea.

Mudpuppie beat me to most of my points. Basically, container gardening is a lot harder than in-soil gardening. And unfortunately you will not get as much of a yield as from the ground, because a) the plants roots are more restricted and b) the whole plant will get too hot since its roots are basically out of the ground... as opposed to when they are in the ground and can stay cooler than the surrounding air.

In answer to your shade question: I think your plants should get enough reflected light to do ok in the shade. Move them back out in the mornings if you think they start looking like they're suffering from lack of light, but give them a few weeks to react first.

But for next year: gardening where you are shouldn't be that difficult. Yes the temps are killer, but with a little preparation it's easier than trying to grow tomatoes in, say, someplace foggy. In the future you should definitely retry traditional gardening. When you do, here are some tried-and-true arid veggie gardening tips:

1) Dig trenches, perpendicular to the slope of your yard (think a "terraced" look almost) about 3 feet deep and 3 feet wide. Keep all the soil in the bottom nice and light, but remove the top two feet.
2) Fill in with one foot of compost and mix lightly - not thoroughly - with the soil you've left in the bottom. (I'm guessing based on your past experience that your poor, sunbaked, desert soil is too poor to sustain vegetables). Yes, this will mean your trenches are sunken by 1 foot - this is based on a Native American technique for collecting any rain water.
3) Get a soaker hose - one of those ones that sweats water - and lay it down in the center of the trench.
4) Set up four posts with wires strung lengthwise. Affix some light-shade fabric to the wires with staples or clothespins. Don't go for heavy fabric or you'll block rainwater.
5) Buy your tomatoes and plant them 18" apart (so 3' down your row you'll have 4 plants) with only the top 4" poking out of the soil (remove any leaves that will be covered in soil). Tomatoes are magical plants that can grow roots all along their stems. This means they will have a yuuuge root system that helps them get all the water they need. (and oh, crumble an eggshell into each hole as you plant. Tomatoes in dry climates tend to get blossom end rot when they are dry and wet and dry again... calcium helps a lot.)
6) Mulch! Mulch like you mean it!
7) Run your soaker hose for about an hour or two once or twice a week, only when you see some wilting.

Erm, sorry for the embarrassing length of this reply!
posted by GardenGal at 8:51 PM on May 20, 2008 [1 favorite]

Arizona Master Gardener Manual
posted by Tufa at 3:46 PM on May 21, 2008

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