Tomatoes in the Desert!

January 21, 2012

I returned home earlier today knowing much less about tomatoes than I left thinking that I knew.  I spent the morning being enlightened by the lovely Leslie Doyle, who’s wisdom is only surpassed by her humility.  The knowledge that I gained this morning would take days to cover, so I am going to focus on her specialty: Tomatoes.  My goal in writing this blog is to dispel many of the misconceptions I had, and that my readers most likely have, about growing tomatoes in the high desert.  I will include links to her website, because I cannot begin to cover the topic with the grace that she does.

Not all tomato plants are created equal.

In a nut shell,  there are many tomato plants that will do well in Las Vegas in the spring.  There are only a few that will last, and produce through the summer.  It isn’t that the plant won’t live, but many of the varieties are “determinant” in that they have a very determined life cycle, and stop producing at some point in the summer.  You want an “Indeterminant” variety.  These plants will grow to maturity and produce fruit until the frost kills them.  That is what we want!  Leslie sells seeds!  I won’t get into growing them.  Visit her website!   I would sincerely recommend both books!  She also has a kit, with everything you will need, for $40.  Not too bad!

Not just any “dirt”

Soil plays a huge role in the success of this project.  Leslie had spent years trying to create the perfect soil on her own, gave up, and has helped a very reputable local company create just that.  It is called Tomato Lady Soil, and it can be bought directly from her by the ton.  It can be picked up, or delivered if you order over 5 tons.  (5 tons may be more than you need, see if your neighbors are into gardening, or borrow a pickup truck on the weekend!) Good soil is important because a great tomato plant with great tomatoes requires a great root system that has access to the nutrients and water that it needs!  I am a very avid proponent of getting trees and shrubs to grow in amended native soil, but in this case it is much better to order it!  Perfect soil also plays a huge part in the movement of water, which in my opinion, is the key to large tomatoes! (More about water later.)

Location, Location, Location!

A common mistake, committed by many, is to locate the vegetable garden in an area that gets morning sun and afternoon shade.  From a horticutural standpoint, it seemed logical to me that a tomato plant would need shade in the hottest part of the day because it has big, tender leaves.  Bigger leaves usually mean less afternoon sunlight in the desert.  Leslie ended that pipe dream this morning.  From a different, and more sound perspective, a tomato plant’s main function is to flower and produce fruit.  With less light, a plant flowers less, and produces less fruit.  What good is a pretty tomato plant that has no flowers or tomatoes? What was I thinking, right?

Water how often?

How do you meet the watering demands of a tender plant like that, out in the full desert sun?  Both Leslie and I have our vegetable gardens on a Netafim irrigation system.  In a nutshell, it is a grid of brown tubing that emits water, like a dripper, in a 12 inch grid evenly across the garden. (Yes, my company can install it, no, it isn’t cheap to do it right.) Spray irrigation gets water on the plants leaves, and all of the disease problems associated with that.  Flood irrigation is great, but not very uniform and is hard to control without oversite.  I like low maintenance, so Netafim works great for me(.9 gph, 12″ spacing).  The garden should be watered enough to keep the soil MOIST down to between 10″ and 18″. Moist is not sloppy.  If you can see water puddles, it isn’t time to water.  If you can stick your finger in the soil and it makes a sound, don’t water. The water needs to have as much air as it does water.  Yellowing is a sign of over watering.  Wilting is also a sign of either over OR underwatering.  Use your finger to determine which it is! (And keep your day job.) Leslie says you can water up to 9 short bursts per day in the summertime!  There is a method to her madness!

A note about the function of soil and water.

As mentioned above, soil is a major factor in the size of the tomato.  Because these plants have big leaves and are in the full sun, and are producing rather large fruit, they transpire an amazing amount of water.  Water that must come from somewhere.  Watering frequently (9 times a day in the summer time) will only provide the water that the plant needs AND not kill the plant, if the soil is well drained.  Don’t skimp on the soil!  Native soil generally has a high clay content and can hold water (and salt) for a long time.  Salinity is not a good thing for these plants, nor is standing water.  (Roots need as much air as they do water.) The principle behind good soil is that it absorbs water quickly, holds it for an acceptable amount of time (so the plant can get it.) then also lets the bulk of it go, taking the salts out of the soil with it.  Sandy soil lets the water go too quickly and has no absorption capacity, as well as no way to hold nutrients.  Most of the “planting soil” from local rock yards is a mixture of sand and mulch, and the mulch usually isn’t very well composted.  That is why I recommend Leslie’s “Tomato Lady” Soil.

Reflective mulch

When I first saw it, I thought the idea was nuts.  The concept however, makes a lot of sense.  Reflective mulch is a thin film of plastic installed over the top of soil.  It is sold at Leslie’s website, listed above, or at Plant World.  It does three major things for the tomato plant.  1) it reflects light back onto the plant.  More light means more photosynthesis, meaning more sugars in the plant, and bigger tomatoes!  2) It keeps critters away! The list is long of insects and birds that don’t like shiny things.  What a great way to kill two (strictly metaphorical) birds with one stone! 3) It helps regulate the temperature of the soil.  Less temperature fluctuation in the plant means less stress. laying a 2×4 on the edge or burying it generally keeps it in place.  The plant should be planted, and then an x cut into the plastic that it can then be worked through.  Who thinks this stuff up?


Plants should be planted about 12″ apart.  That really sounds like a jungle to me, but we want them to cool each other, so there you go.  PLUNGE the plant.  Say what? Plunging is when you bury all but the top couple of inches of plant.  It goes against all horticulture principles, and don’t try it on your trees, but it really does help generate more root zone for the plant, giving them a leg up!  The stem of the plant generates more roots! Make sure you pull off all of the leaves that are going to be on the area of the stem you are plunging.  Leslie recommends installing a  plastic cup (take off the bottom) in the soil, about an inch deep, around the plant to protect it from cutworms, bugs and the wind.  Plants should not be put outside until the nighttime lows are consistently above 50!

Planting with Fertilizer and Foliar Fertilizer

Here I am being different again.  Please don’t use miracle grow or lawn fertilizer on your tomato plants!  The nitrogen content is too high.  You will just get big plants.  Go find a nice organic vegetable fertilizer. 5-10-5 is perfect.  Scratch it in to the bottom of the  hole and the top of the soil when you plant. In addition,  Foliar Fertilizer is any fertilizer that you spray onto the plant, rather than put into the soil.  Leslie recommends applying Kelp Extract three times during the growing season.  Spray them down well with your hose-end attachment before the sun comes up.  If the solution is balling up on the leaf you need a surfactant.  The best surfactant is dawn dish soap. Add a few drops to the solution.  You will know you are adding enough because the water wont create a ball on the leaves anymore.


My wife doesn’t like hornworms.  They ate a good part of a couple of her tomato plants a couple of years ago and even munched on our citrus tree.  “Die Bug” is a powder that can be sprayed onto the leaves.  It is a food grade Diatomaceous Earth product that is very effective.  Another, more long term, effective method is to kill the moths that fly around your lights at night, they are the ones that will be laying next years caterpillar crop.! You can also go out into the garden at dusk and search the leaves for the little devils.  Beware, they are pretty big! Leslie also claims that Red Wine is a fine solution.  She doesn’t spray it on or put it in the soil, she drinks it while she looks for them.  It makes the job more tolerable!

Tomato Shade

Tomatoes themselves do not photosynthesize.  They do not need any sun.  You can shade them to protect them from sun scald by draping them with a 1′ x 2′ piece of shade cloth folded in half.

Other notes:

Don’t stake your tomatoes!  The closer the tomatoes are to the ground, the cooler and bigger they will get!


Happy planting! Let me know if you need any help!

Ben Johnson




Leslie Doyle 2003

Leslie’s email is:



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