Growing Herbs in Scottsdale [split from Southwest]
(Note: This thread was split from the Southwest board at: http://chowhound.chow.com/topics/6098... -- The Chowhound Team).
I have tried growing herbs here in Scottsdale. I have not had much luck, I don't know if its over / under watering. Would love to have basil, mint, oregano, thyme just a snip away :)
I lived in Mesa for more than 15 years and am now in Gold Canyon for the past 7 years. Amazing what a climate difference 35 miles makes. I've had both great luck and abysmal failures growing herbs as well as vegetables, fruit, etc. in both places. They're very different and I've learned as I've gone along.
Here's a synopsis of what I learned:
#1 - In-ground planting is preferable to pots, especially in the summer. The plants in the earth have better heat protection for their roots than those whose roots are up and exposed in pots. This probably quadtruples if you're using metal pots (think heat exchange) like those handsome copper or zinc pots from Smith & Hawken. The bigger the pot, the better chance you have of success. Half whiskey barrels, as suggested by hohokam, and large terracotta pots, suggested by ziggylu, are great; some afternoon shade, in the summer, is even better. There is no way that any pot under 14" will succeed in the summer, I don't care what you see in magazines. I prefer larger than that but there is a monetary tradeoff as well. Big, big pots are not cheap and are harder to move when necessary. I have numerous herbs in large pots since I moved and have met with mixed success. Sometimes it is the local wildlife who are culprits, other times ??????? I have citrus trees in large pots and they're doing well. One Meyer lemon faces east against a wall while the second Meyer faces south and is shaded from afternoon sun by mature trees. I grew Meyer lemons in the ground in Mesa and they grew faster and produced more fruit than these in pots. Ditto for the oranges but I have no choice here. If I want cirtus trees, they're in pots. Period. HOA etc.
#2 - forget almost everything you learned about gardening somewhere else. The zone charts are not much help here since they track nighttime lows instead of daytime highs. Get good planting advice from a nursery close to where you live; do not rely in what is available in HD etc. Large chains get what's also being shipped to Southern California at this time of year and LA has no relation to what happens in our valley. Experiment and keep trying.
#3 - Great drainage and adequate water = mandatory. Clay pots are more porous than plastic, therefore need more water due to evaporation. In high summer, I've had to water some pots of mint twice a day, even when shaded. Rosemary is much more forgiving. Some years thyme summers easily, others it dies, ditto for sage. I have never had continuous luck with tarragon. I cannot use the Mexican oregano or basil fast enough when they're growing happily.
#4 - Learn your particular "micro-climate" in your yard. N S E W are good places to start but do not tell the whole story. A south-facing wall that's shaded is not the same as a full-sun south facing wall; and anything placed up against a wall is going to get full radiant heat from that wall. This is a plus in the winter and not a good idea in the summer.
#5 - good soil. I cannot stress this enough. Use potting soil or dirt mixed with your own compost plus potting soil. Plain dirt is not sufficient to support healthy, year-round plant growth in pots. Remember this is like having an animal in a cage - it is completely dependent on you for all its needs. Nothing flourishes without good soil and enough water.
Sherri really knows what she's talking about. I would add this- be sure you like epazote before you plant it because it self-sows like mad and you'll never be without it again, for better or worse.
Five years ago I moved from a house that I had complete Zen-like knowledge of the back yard and what it was capable of to a house five blocks away that was laid out totally differently. I'm still trying to get used to it. So #4 is really important.
We haven't found most herbs to be that picky. As long as we've provided them with proper drainage and (a) full sun fall through spring and (b) full sun with afternoon shade in the summer, they've seemed happy. Over the 17 years we've been gardening in the Valley, we've had good luck with mint, Greek oregano, Mexican oregano, epazote, various basils, English thyme, and marjoram (and catnip, which the kitty appreciates). The only plants we've consistently had problems with are parsley and cilantro, both of which have tended to bolt before they've gotten very big.
One mistake that I think some people make is to try to grow herbs in cute little window box type planters, which IMO don't have the soil mass required to hold water enough water to help moderate effects of extreme air temperatures. My advice is to get as many half barrel planters as you have room for, drill holes in the bottoms (drainage, drainage, drainage), and to fill them with a high quality potting mix. Mint will eventually take over whatever container it's put in, so one needs to plan accordingly. We've had success growing things like thyme and oregano with largish terra cotta pots (12"-14" in diameter at the top), but basils can grow quite large and need plenty of room for their concomitantly large root systems.
Come summer, all of the herbs planted in the spring will need daily watering.
I agree with the recommendation for Bakers.
Also agree with teh planting advice of hohokam's. I"ve had good luck with herbs in big terra cotta planters, no more than two in a planter. Mint gets its own. I have basil, mint, lemon thyme, cilantro, pineapple sage and oregano growing right now and they're all really happy. The basil wintered over from last year. When the real heat comes I move everything under the citrus trees until the nights start cooling down a bit again. Everything is on a drip system and it gets adjusted accordingly with the weather.