How To Grow Dryland Corn With Less Than 10 Inches Annual Precipitation
Drought Tolerant Corn Varieties
We focus on Hopi flour corn varieties because they are high in carbohydrates, store well, and they can be grown without irrigation in areas with less than 10" of annual precipitation. There are many more Pueblo corn varieties than those listed here. Here are the varieties we have tried and recommend.
- Hopi White - Flour corn, 5-6 feet tall, plant deeply, makes many tillers.
- Hopi Pink - Flour corn, 5-6 feet tall, makes many tillers.
- Hopi Blue - Soft flour corn, 5-7 feet tall, usually no ears on tillers.
- Smoik Hu:n - Early flour corn, 5-7 feet tall, tillers well.
- Concha White - Flour corn, 5-8 feet tall, tillers well, susceptible to corn smut.
- Wikti (Hopi Greasy Head) - Early flour corn, 4-5 feet tall, tillers well, susceptible to corn smut.
- Kikam Hu:n (Pima 60 Day Corn) - Early 80% flour 20% flint corn.
- Hopi Turquoise - Flour corn, did not produce in strip-till planting test.
- Hopi Purple - Flour corn, did not produce in no-till dibbled planting test.
Hopi White is one of the best type for dry conditions and deep planting. Hopi Pink seems to be the most productive with up to 8 ears per plant, and ears can be very colorful. Hopi Blue makes very large dark ears with soft flour kernels that are easy to grind into flour. Concha White plants can get really large with 8 full sized stalks per plant and up to 7 ears. Hopi and other pueblo corn varieties can survive without irrigation, but require much more space per plant to produce well even with irrigation.
Pueblo landrace corn varieties are older compared to commercial corn varieties can display a wide variety of unusual characteristics. Sometimes kernels are present on the tassel, ears may have a tassel on the end , and stalks can have ears at the terminal/top/tassel node, see the picture labeled "Hopi Pink / Ears On Tassel". It is likely that Teosinte, the wild ancestor of corn, produced ears with tassels on the terminal node as well as on lower lateral nodes, but as corn ears got bigger and heavier corn evolved to produce ears only on the lower lateral nodes. Heavy ears at the tops of the plants would increase the chances of lodging. The terminal node at the top of the plant became specialized to produce only pollen facilitating transport of pollen grains to the silk of lower lateral nodes.
Hopi Corn Precipitation Requirements
Hopi corn is traditionally grown in Arizona with less than 10 inches annual precipitation and little rain from April to the end of July. It can survive several months without precipitation. We grow Hopi corn in north central Washington with 10 inches of annual precipitation most of which is winter snow and almost no rain from mid June to mid September.
According to Michael Kotutwa Johnson the Hopi have no rain from April to the end of July so I looked up some numbers. Monthly totals can be a little misleading since in Okanogan the table shows June and September has having about 1 inch of rain but last half of June and first half of September are usually dry. This year was unusual and we had 0.5 inches of rain on August 20th but no more to date and it is now October 3rd. In both regions the dry period is 3 months long with the dry period in Okanogan being later in the year. The bulk of precipitation in Okanogan is in winter months in the form of snow. In Arizona the Hopi plant corn in mid April when soil the in Okanogan is still too cold for corn to germinate. I have successfully planted in late April and mid May but the time of emergence of the April planted corn was delayed and similar to the May planted corn.
Monthly Avg. Precipitation & Hi / Lo Temperatures Last 10 Years | ||||
|---|---|---|---|---|
| Arizona | Okanogan | |||
| Precipitation | Temperature | Precipitation | Temperature | |
| January | 0.8 | 43°F / 27°F | 2.4 | 33°F / 21°F |
| February | 0.6 | 49°F / 30°F | 1.3 | 37°F / 22°F |
| March | 0.6 | 57°F / 36°F | 1.7 | 46°F / 30°F |
| April | 0.2 - dry | 67°F / 43°F | 1.1 | 57°F / 37°F |
| May | 0.3 - dry | 76°F / 51°F | 1.2 | 69°F / 45°F |
| June | 0.2 - dry | 88°F / 63°F | 0.8 - partly dry | 77°F / 51°F |
| July | 0.5 | 91°F / 70°F | 0.2 - dry | 87°F / 59°F |
| August | 0.7 | 89°F / 68°F | 0.3 - dry | 86°F / 58°F |
| September | 0.4 | 82°F / 60°F | 0.7 - partly dry | 75°F / 49°F |
| October | 0.5 | 68°F / 46°F | 1.6 | 58°F / 38°F |
| November | 0.5 | 55°F / 34°F | 2.2 | 42°F / 28°F |
| December | 0.7 | 44°F / 28°F | 2.5 | 32°F / 20°F |
When To Plant Hopi Corn?
Plant when soil temperatures at a depth of 8 inches is 50°F or higher. Since Hopi Corn is planted deeply it can be planted 2 weeks before the last expected frost date and it will emerge from the soil after that date. Planting earlier will not result in earlier emergence because cool soil temperatures will delay germination and increase the chances of seed spoilage. For us the idea planting time is between May 1st and 31st where last expected frost date is May 15th.
How Many Days To Maturity For Hopi Corn?
Days to maturity can vary a little depending on the variety, but most Hopi corn varieties can be harvested at the milk stage to eat as sweet corn by 60-80 days. For saving seeds it takes 120 days or more before kernels are ready to harvest, and additional time may be needed to dry down before storage. In our area it is best to get all varieties planted before June 1st and and harvest at the end of September.
Planting Location - Where To Plant Hopi Corn?
Look at type and size of existing vegetation before clearing an area to plant. Rabbit brush and big sagebrush indicated the presence of ground moisture and healthier and bigger existing plants indicates more available ground moisture. Short grass that dries early in summer indicates less available ground moisture and/or poor soil that may requires additional fertilizer. Hopi corn roots can extend up to 10 feet deep and 10 feet horizontally in search of nutrients and moisture. Ground water is closer to the surface on the lower side of slopes and areas that collect water during summer rains are good places to plant.
How to Clear for Planting Dryland Hopi Corn?
Clear the selected location of all vegetation to reduce competition for water. Clearing all vegetation and spacing hills far apart exposes the soil to erosion and damage by high winds. To mitigate this cultivate smaller fields of an acre or less, orient fields or strips of cultivated area perpendicular to prevailing winds, and leave natural vegetation or plant a dryland legume cover crop (like alfalfa) between fields. To reduce erosion space plants evenly and a distance less than three times their height. For Hopi corn choose a row of spacing 12 feet or less. Most of our fields are 80-100 feet wide but several hundred feet long.
How Far Apart to Plant Hopi Corn?
Suggested spacing for dryland Hopi corn is 12-25 sq. ft. per plant or 4-7 plants in hills 9-12 feet apart.
The root system of Hopi Corn extends horizontally much more than expected compared to other similar sized crop plants. Plant in blocks 6-20 feet apart by making a hole and puting 7-10 seeds per hole. Reducing plant density reduces competition for ground water and this is much more important than reducing evaporation by early canopy closure (close spacing). Plant deeply 6" or more and plant multiple seeds per hole to ensure enough seedlings emerge in each block. These will be thinned later to 4-7 plants per block. A single kernel can develop as many as 6 stalks (main stalk plus tillers) with as many as 7 ears of corn. In each block stalks provide each other with protection from the sun, the wind, summer heat, and shield ears developing in the middle from animals. Each plant needs 12-25 square feet or more depending on conditions.
When Hopi Corn is planted too closely plants at the ends of rows do better than plants within the rows and outside rows do better than inside rows. In the experiment below Concha White was planted closely in a square to test the benefits of early canopy closure. The plants on the outside of the square had less competition for ground water, stayed green, and made ears while the corn in the middle dried out and died.
Hopi White / End Of Row 1
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Hopi White / End Of Row 2
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Concha White / Square Dry In Middle
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Concha White / Green South Edge
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Dry Middle / Green North Edge Behind
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Hopi plant in blocks 3-7 paces apart. A search engine result says to plant in blocks 4.9-5.7 feet apart, but I can find no scientific papers or sources to support this spacing. In videos by Michael Kotutwa Johnson the hills look to be 7-10 feet apart and in one case he used a tractor to plant in 6 foot rows. In another video the farmer took 3 long paces and then used a hoe to make a hole 3 feet further or 4 paces / 12 feet between hills. Akima plants in hills, thinned to 4-7 plant per hill, 3 paces by 3 paces apart with hills staggered so hills in a row are midway between hills of adjacent rows. In another video Akhima says "4 steps in between" with 4-7 plants per hill. This comes out to between 11.57 - 36 sq. ft. per plant. Collins has pictures of hills 20 feet apart with 10 - 20 plants per hill which is 20 - 40 sq. ft. per plant. The average of 11.57 and 40 is 25.8 sq. ft. per plant. This is a much lower plant density than the 2 ¾ and 3 ¾ sq. ft. per plant I used in 2023 and 2024 respectively. Most Hopi varieties I have tried develop multiple stalks from tillers and can produce up to 7 ears per plant so 4-7 plants per hill may not be necessary. Conversely more plants per hill may inhibit tiller formation resulting in a similar number of stalks per hill. Optimal spacing for a given location will depend on soil type, ground moisture, and local weather conditions.
What are the Yield Estimates for Dryland Hopi Corn?
My biggest mistakes have been planting too closely and focusing on yield per acre. If a large area of unused arid land is available for planting (take land area out of the equation) then increasing yield per resources and labor inputs becomes the main objective, not yield per acre. Yields are understandably less than expected compared to an in a irrigated field. An ear of corn can have between 0.25 and 0.8 lbs of kernels and irrigated Navajo corn produces an average 0.95 lbs per plant. One acre 43560 sq. ft. / 25 = 1742.4 plants per acre X 0.95 = 1655 lbs / 56 = 30 bushels. This is only an estimate and yield could be higher or lower based on several factors, but it seems reasonable optimized spacing could yield 30 - 50 bushels per acre since dryland wheat yields 42 bushels/acre in Washington State.
How Labor Intensive is Planting Hopi Corn?
Traditional Hopi farming relies on manual "labor intensive" methods, and I have tried different planting methods to increase yield and decrease resources and manual labor needed to grow Hopi corn. A tractor can be used for clearing, spreading fertilizer, tilling in fertilizer, making a trench to plant, and backfilling, but without specialized tractor equipment deep planting and thinning must be done manually. For manual planting using a drill with a garden augur significantly reduces the labor needed to plant. Planting manually in hills far apart only requires taking a few more steps between hills and requires about the same effort (bending down and digging) per hill as planting close together. Planting multiple seeds in hills ensures some will emerge in each location and requires less effort than planting individually.
What are the Benefits of Planting Corn in Hills?
Planting in hills reduces the labor needed to grow and harvest corn. Planting corn individually means it is necessary to bend down, make a hole, plant seed singly, and later thin and harvest plants individually. Planting in a hills makes it possible to plant and tend several plants at the same time, eg more yield for less effort. It is also advantageous since plants within a hill can support each other and reduce lodging in windy areas, though it may also lower per plant yield due to increased competition for water and nutrients.
Some Hopi farmers plant from a bowl where seeds from different ears are combined while others take seeds directly off an ear and put these in one hill. This will have an effect on genetic distribution that is not obvious initially. In the first case every hill is planted with kernels from different parent plants and traits will be averaged out or diluted. If seeds in a hill are planted directly from the cob all progeny plants in a hill and nearby hills come from the same parent and they will all be somewhat similar. Ears from a hill have a slighly higher likelyhood of being pollinated by plants in the same hill and nearby hills (which may have also been planted from the same ear). In the next year a cob is taken with all the hills nearby again providing pollen with even less diversity intensifying any traits in the original parents. Corn cross pollinates readily over distance so inbreeding depression is not likely but planting in this way will amplify desirable characteristics assuming only seeds from plants with desirable traits are planted. The overall effect is to amplify traits hastening the process of artificial selection and strain improvement. It is also similar to selecting seeds with desired traits and planting them in a separate field to create a new variety. This would be something I might try if I had an ear with unusually pretty colors that I wanted to get more of the next year but not yet isolate from the general population.
| Hill Spacing for Dryland Hopi Corn? | |||
|---|---|---|---|
| Plant Density | Hill Spacing | Plants / Hill | Hills / Acre |
| 12.00 sq. ft. / plant | 4 x 3 | 1 | 3630 |
| 15.00 sq. ft. / plant | 5 x 3 | 1 | 2904 |
| 12.00 sq. ft. / plant | 6 x 2 | 1 | 3630 |
| 18.00 sq. ft. / plant | 6 x 3 | 1 | 2420 |
| 24.00 sq. ft. / plant | 6 x 4 | 1 | 1815 |
| 12.00 sq. ft. / plant | 6 x 4 | 2 | 1210 |
| 18.00 sq. ft. / plant | 6 x 6 | 2 | 1210 |
| 12.00 sq. ft. / plant | 6 x 6 | 3 | 1210 |
| 27.00 sq. ft. / plant | 9 x 6 | 2 | 806 |
| 18.00 sq. ft. / plant | 9 x 6 | 3 | 806 |
| 13.50 sq. ft. / plant | 9 x 6 | 4 | 806 |
| 10.80 sq. ft. / plant | 9 x 6 | 5 | 806 |
| 24.00 sq. ft. / plant | 12 x 6 | 3 | 605 |
| 18.00 sq. ft. / plant | 12 x 6 | 4 | 605 |
| 15.40 sq. ft. / plant | 12 x 6 | 5 | 605 |
| 12.00 sq. ft. / plant | 12 x 6 | 6 | 605 |
| 10.28 sq. ft. / plant | 12 x 6 | 7 | 605 |
| 40.50 sq. ft. / plant | 9 x 9 | 2 | 538 |
| 27.00 sq. ft. / plant | 9 x 9 | 3 | 538 |
| 20.25 sq. ft. / plant | 9 x 9 | 4 | 538 |
| 16.20 sq. ft. / plant | 9 x 9 | 5 | 538 |
| 13.50 sq. ft. / plant | 9 x 9 | 6 | 538 |
| 11.57 sq. ft. / plant | 9 x 9 | 7 | 538 |
| 27.00 sq. ft. / plant | 12 x 9 | 4 | 403 |
| 21.60 sq. ft. / plant | 12 x 9 | 5 | 403 |
| 18.00 sq. ft. / plant | 12 x 9 | 6 | 403 |
| 15.42 sq. ft. / plant | 12 x 9 | 7 | 403 |
| 36.00 sq. ft. / plant | 12 x 12 | 4 | 303 |
| 28.80 sq. ft. / plant | 12 x 12 | 5 | 303 |
| 24.00 sq. ft. / plant | 12 x 12 | 6 | 303 |
| 20.57 sq. ft. / plant | 12 x 12 | 7 | 303 |
| 40.00 sq. ft. / plant | 20 x 20 | 10 | 109 |
| 26.67 sq. ft. / plant | 20 x 20 | 15 | 109 |
| 20.00 sq. ft. / plant | 20 x 20 | 20 | 109 |
How Much Fertilizer is Needed for Dryland Hopi Corn?
The roots of corn plant extend up to 10 feet around each hill to reach water and nutrients and broadcast fertilizer recommendations need to be adjusted to compensate for plant density and removal of nutrients by the crop. In Georgia dryland corn is planted 16000-18000 seeds per acre, but the average annual rainfall in Georgia is 50 inches and dryland yield can be more than the national average for irrigated corn. The suggested fertilizer rates for dryland corn in Georgia is 120-80-80 lbs. per acre, assuming a yield of 100 bushels/acre. Since Hopi corn is typically grown at at 10 times lower plant density with much less rainfall, fertilizer rates need to be adjusted for expected yield.
My supplier doesn't have and won't mix in Iron or Magnesium, and Zinc is either included in MESZ, added separately, or not at all. If my supplier does not have 1152 I use MESZ. Adjust the values below for the size of your field. It is a good idea to get a soil test and only add the "other supplements" if needed. I use more K20 than the 120-80-80 recommended by UGA.
Previously we calculated an expected yield as 30 bushels per acre which is not far from 42 bushels per acre for wheat. Optimistically assuming dryland Hopi corn planted with optimal spacing can make 50 bushels per acre, fertilizer should be reduced by half and an application rate of 60-40-40 lbs per acre should be sufficient to maintain the crop. I recommend if planting fallow or previously uncultivated land to use the values below for the first year to determine the maximum yield when fertlizer is not limiting and then reduce values in subsequent years by multiplying the values below by the first year yield in bushels/acre divided 100 (the fertilizer rate for dryland corn in Georgia assuming expected yield of 100 bushels/acre). So for example if first year yield is 30 bushels then 120lbs of Nitrogen x 30 bushels/100 bushels = 36lbs of Nitrogen for the second year.
| Fertilizer for 1 acre of corn using 1152 assuming 100 bu/acre | |
|---|---|
| 225 lbs Urea 46-0-0 | N 103.5 lbs/acre |
| 150 lbs 1152 11-52-0 | N 16.5 lbs/acre + P205 78 lbs/acre |
| 166 lbs KCl MOP 0-0-60 | K2O 99.6 lbs/acre |
| 18 lbs MnSO4 28% | Manganese 5 lbs/acre |
| Boron Coating | - added by supplier - |
| Nitrogen Stabilizer | - added by supplier - |
| Fertilizer for 1 acre of corn using MESZ assuming 100 bu/acre | |
| 208.7 lbs Urea 46-0-0 | N 96 lbs/acre |
| 200 lbs MESZ 12-40-0-10-1 | N 24 lbs. - P205 80 lbs. - Zn 2 lbs. |
| 166 lbs KCl MOP 0-0-60 | K2O 99.6 lbs/acre |
| 18 lbs MnSO4 28% | Manganese 5 lbs/acre |
| Boron Coating | - added by supplier - |
| Nitrogen Stabilizer | - added by supplier - |
| - other supplements to add once or if soil tests low - | |
| 52 lbs FeSO4 31% Iron Monohydrate | Iron 16 lbs/acre |
| 30 lbs Zinc Sulfate 35% Zinc | Zinc 10 lbs/acre if not using MESZ |
| 50 lbs MgO 45% Magnesium Oxide | Magnesium 22.5 lbs/acre (*50-100) |
Hopi Corn - Seed Preparation / Pre-Sprouting
It is best to soak the corn seeds before planting but it is not necessary. Seeds should be soaked at least 8 hours before planting. Old seeds may be dry and benefit from multiple soak/rest cycles. Soaking more than 12 hours can damage seeds due to a lack of oxygen so it is better to soak 8-12 hours, drain, rest 8-12 hours, then soak again 8-12 hours, and repeat until roots begin to develop but are not extending from the kernels. Seeds which are too far along in the germination process and have emerging roots are easily damaged by handling. It is best to discard floating seeds which may not germinate and it is better to plant soaked seeds right away as refrigeration can damage soaked seeds. We soak our seeds overnight, drain in the morning, rest for 8-10 hours, and plant the next evening.
How Deep To Plant Dryland Hopi Corn?
Plant Hopi Corn deep enough to contact moist soil or 6-12 inches deep. Hopi corn is adapted to deep planting and deep planting helps seeds absorb enough water to reach the soil surface and later reduces lodging. We have had poor emergence planting single seeds deeper than 12 inches so if planting deeper (to reach moist soil) use the hill method with 10 or more seeds per hill.
How To Plant Dryland Hopi Corn?
Till the soil to remove all competing vegetation, spread fertilizer, and till in the fertilizer in before planting. A cultipacker can be used to firm the soil before planting which will also reduce evaporation, loose tilled soil looses water more quickly. Make a hole 6 to 12 inches deep and deep enough to reach moist soil. If the surface is dry it is best to scrape a clear area, remove the soil by hand, plant 7-10 kernels, and place the moist soil back in the bottom of the hole with the top dry soil back on top. We use a 2 inch augur with a drill and drill an 6-8 inch hole, plant the seeds, and push the soil back in the hole. To ensure that holes don't collapse before seed placement and no holes get missed, it is better if one person drills the holes and a second follows behind planting seeds. Push the soil with a shoe or hoe to cover promptly reducing soil evaporation and the chance that exposed seeds will be eaten by wildlife. If using an augur and doing many hills an extension cord drill will work better than a battery powered drill. Use a generator, solar generator, or if power is available use as many 100 ft. light duty extension cords as needed to reach planting areas. The drill will get hot after about 400 holes and needs time to cool down or it can be swapped for another drill. After planting do not drive a tractor directly over planting holes. It is beneficial to water each hole sparingly if the soil is very dry.
If planting in furrows with a tractor, a middle buster can be used to make a 12 inch furrow and corn planted at the bottom of the furrow. Plant only one row in the middle of the furrow either singly or in hills at the desired spacing. Pull a rebar harrow behind the tractor to fill in the furrows by driving on the high parts between the furrows. Make sure to make enough passes and put the tines on the harrow down for at least 1 pass to get adequate coverage. A cultipacker can be used to firm the top of the furrows. If furrows are not well filled, soil moisture loss will be higher, plants root structure will not be as strong, and plants will be more easily toppled by wind or rain.
How to Thin & Hill Dryland Hopi Corn?
When the corn is 8-12 inches tall remove a couple inches of soil around the plants in each hill and remove the weakest leaving 4-7 plants per hill. After thinning pull surrounding soil back around the stalks and firm the soil. If corn was planted in a trench or depression move soil to fill in the depression and as the corn gets taller hill extra soil around the base of the stalks. The extra soil provides extra support and acts as an inorganic mulch to reduce evaporation.
Hopi Corn Pests & Diseases
Grasshoppers, birds, and rodents can damage corn and reduce yield. Tilling kills grasshopper eggs in the soil. For organic control of grasshoppers spread a 4 foot band of diatomaceous earth with a flour sieve around the field and between every 4 rows. Grasshoppers hop onto the treated areas and they will die after a few days. For a small field put screen sleeves over the top of the ears which allows pollination but prevents grasshoppers from eating the silk, though in theory silk will continue to elongate until pollinated. The screen can be left on to reduce damage by birds. Birds peck through the husk at the top of ears but usually only part of the ear is damaged. For rodents mouse traps with peanut butter are effective. Corn smut is a fungal disease that causes kernels to become enlarged and grey colored. It can infect several types of Hopi Corn, and some corn varieties are more susceptible than others. While some farmers consider corn smut a loss, in Mexico it is cultivated and eaten as a delicacy called Huitlacoche.
How to Harvest & Store Hopi Corn?
Hopi Corn can be harvested at the immature milk stage for eating fresh like sweet corn when the silk has turned brown. If harvested earlier the kernels will not be as sweet or fully developed and if too late will be slightly starchy. Blue corn is sweetest when still white but gets starts to get starchy just as it starts to turn from white to blue.
If planning to store the corn or use it for seed leave it as long as possible on the stalk or until the husks are dry. Mature corn that has already bent in a downward direction is usually ready to harvest. Discarding some of all of the husks in the field reduces work later and provides mulch for next years crop. Bend the ear near the base below the lowest row of kernels until it snaps off. Husks attached below the break point will stay with the plant and the remaining ones are easily removed. Discard the silk. If harvested too early the silk will be green and fresh, and it is better to process these ears for eating or to wait longer before harvesting ears with simliar appearance.
Immature corn kernels will have a lower germination rate. Hopi Blue Corn that is dark or medium blue should have greater than 90% gerimination rate while lighter colored less mature blue corn will have a germination rate of 75% or lower. For long term storage allow corn to dry in the field till moisture is less than 15%. Corn will dry rapidly when temperatures are high and humidity is low but decreases to 0.4% percentage points per day when average daily temperature is 55°F. Corn that is not yet dry on the stalk can be damaged by freezing temperatures resulting in decreased seed viability. Late harvested corn can be brought indoors finish the drying process. If moisture higher than 15%, it is better to dry it on the cob with ventilation or mold could grow decreasing the viability of the kernels.
What Cover Crops To Use For Dryland Hopi Corn?
Hairy Vetch is legume cover crop that will add nitrogen to the soil, and it grows well during fall and spring when temperatures are cool. Plant in the fall after harvesting corn and kill the following spring by crimpling or tilling before planting corn in May.
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