Growing Tortoise Foods in Desert Soils

Can you grow healthy foods for tortoises in desert climates?  Absolutely!  Wild, arid species of tortoises need something to live on, right?  People who live in desert regions know that the desert is anything but a dry, hot, desolate place where nothing grows.  When conditions are favorable after sufficient winter rains, deserts become awash with billions annual and perennial native forbs, wildflowers, and grasses.

By understanding the unique life cycles of native plants, and by trying to copy what seeds require in order to germinate and grow, there are many species of plants that we can successfully grow for our tortoises.

Basic needs for desert native species of plants

Many species of desert plants throw deep tap roots early in the growing process.  If planted in shallow containers, or in soil in which they can’t spread roots quickly, they don’t often survive for long.

Soil:  Desert plants thrive in areas where soil is considered by gardeners to be “poor.”  There is not a lot of organic matter in sandy/gritty/rocky desert soil.  Alkaline soils that drain extremely well are a necessity.  Caliche (clay) soils may be impossible to grow most species of plants.  It is recommended to plant only if the caliche layer can be “punched through” to access more favorable soil.

Stratification:  Seeds left in soil over the winter, where they are exposed to fluctuations in temperature and cold, moist soil helps seeds to break dormancy.  Many seeds have natural inhibitors in the seed coating, to protect the seed from germinating when there is not enough winter rain or the soil doesn’t remain moist for long enough to allow the seed to establish.  Several regular soaking storms are required during the winter months, which helps to remove inhibitors, and allows seeds to “wake up” as moist soil warms up, the days grow longer, and the sun becomes stronger.  This may be as early as February in low desert elevations.

Scarification: Some seeds have extremely hard seed coats, and need to have their seed coats “nicked” in order to allow moisture into the seed.  Nature accomplishes this in several ways.  Wind or water may cause seed to travel across abrasive, sandy soils.  Others are scarified when animals eat them, and the seed coat is softened or broken as the seeds pass through the digestive tract.  The scat, containing seeds, acts as a fertilizer..

Harvester Ant nest entrance: Central Mojave Desert, California,  A single nest may have more than one entrance.  A queen Harvester Ant may live for up to 40 years!

Ants:  Many desert gardeners make the mistake of planting seed before native Harvester Ants have stopped activity for the season.  Where present, a Harvester Ant colony can find and collect every seed in the environment.  The author has witnessed Harvester Ants remove every seed from a newly planted lawn. Seeds are taken into their large nests, where all chaff and seed hulls are cleaned from the seed.  Once clean, the hulls are carried up to the entrance of the nest, where they are deposited, in a circular shape.  As the warm season wears on, some nest entrances obtain a debris ring of impressive size, sometimes as larger in circumference than a large truck tire.

Rodents:  Desert rodents, to include several species of mice, pack rats (also called wood rats) and kangaroo rats will all take advantage of planted seed.  When planting, always protect seed beds with a 1/4 inch mesh hardware cloth until a few days after germination.

Rabbits and Hares: Desert cottontail rabbits, and black tailed jackrabbits are more than happy to help themselves to a buffet.  Areas containing seed can be “caged” to prevent damage. If jackrabbits are present, protection will need to be 4 feet from ground level.

Ground Squirrels:  While some species of desert ground squirrels aren’t terribly invasive, they can cause severe damage to root systems.  The antelope ground squirrel, for example, digs small burrows several inches away from a plant. Once they access the roots, they will eat them all.  Entire hedges of cactus have literally fallen over, once there are no roots left to anchor the plant, and dead plants are often the final result.  This type of damage can be easily prevented by caging the plant below ground as well as above, 12 inches below the soil surface, using 1/4 inch hardware cloth. “Gopher baskets” are often ineffective, due to this squirrel’s very small size.  For protection from California ground squirrels, cage as you would for rabbits or hares.

If all of this hasn’t completely turned you off to the idea of growing native forage for your tortoises-read on!  These are basic tips for growing seed outdoors in native soils.

For best results, wait until nights remain under 50 degrees.  Always loosen soil first, and make a bed several inches deep. DO NOT amend soils with fertilizers or compost!  If using a planter box, loosen soil, remove it to a depth of several inches, and place hardware cloth at the bottom. Replace the soil, raking it in evenly, and give it a thorough, but gentle soaking.  After soil has drained, but is still damp, follow instructions for planting seed at recommended depths. Too shallow and severe weather may harm seed, or birds may find it.  Plant too deeply, and the seeds may not have the strength to reach the surface.  For the late fall and winter months, monitor weather.  Water lightly but thoroughly beginning in mid-December if there has been no rain. If a period of more than 3 weeks passes without rain, and the soil starts to feel dry when inserting a finger into the soil, re-water, and continue to do so if there is not sufficient rain.  A single rainstorm can keep soil moist for weeks, so it is important to check soil moisture before considering watering.  It may help to leave an area free of seeds. a quick dig with a small garden spade will make inspecting soil easier.