I also meant to say you need to understand your soil and the sun conditions at various parts of your land in relation to what you want to grow.
Here are some factors to consider:
soil: slope, clay content, acidity, drainage, temperature, compaction, nutrient density
sun conditions: walls, trees, shade from structures and other plants
seeds: make sure they produce plants with viable seeds of their own so you can keep planting them year after year. Consider how to germinate, planting depth, time to plant (you may need cold frames for late frosts--I lost my early tomato crop last year this way), root profile (for crowding with other plants) and spacing, sun and water requirements, suitability for your soil conditions.
Here are a list of further suggestions. Apocalypse or no apocalype, you can save a bundle growing your own food, and eat better and more healthily too.
1.) Grow your own sprouts. With organic sprout seed and a few washings per day, you can eat fresh sprouts. Any kind of seed can be sprouted. You can buy bulk seeds on amazon.com
grains: wheat, spelt, kamut
beans: mung, adzuki, lentil, chickpea
vegetables: radish, broccoli, cress, mustard, peas
Sprout safety tips: make sure you consume your sprouts early and often, and sanitize sprout containers between sproutings. You can begin consuming sprouts when they are as small as 1/2 cm. Also, thoroughly rinse sprouts under plentiful water while sprouting, and try to keep sprouts as dry as possible while they are being consumed/stored (remove excess hulls which might trap water). Throw out any sprouts whose safety you might have a question about it.
2.) Grow microgreens in trays. This way you can grow through the winter indoors.
Microgreens are the same thing as greens, but they are baby varieties.
The same things that start out as sprouts also make good microgreens. Other good microgreens
include sunflower (sprouted from unhulled seeds), buckwheat, arugula, spinach etc.
3.) Green manures.
...in case fertilizer is unavailable. Examples are clover and vetch. Sow seeds and plow under at a certain point. Works like fertilizer.
3.1) Compost piles
Save all vegetable scraps for composting. Mulch all leaves and branches.
4.) Fruiting trees and bushes
Apricot, apple, fig, pomegranate etc.
5.) Sprout seeds --> seedlings --> transplanting outdoors
gives you a leg up on the growing season. Can also extend growing season with cold-frames.
6.) Intensive gardening or gardening a small area intensively.
See books like "grow more vegetables" by John Jeavons.
7.) Drip irrigation
Saves water and gives good results. Proven technique for desert agriculture.
8.) Sunken beds.
Here in the desert you want to catch the rainwater (unless you are irrigating with the Rio Grande).
The indians always planted in sunken beds. Similarly, you can redirect rainwater from your roof into
your garden using some kind of irrigation system.
9.) Strategic planting of plants next to each other to minimize pest problems.
Some plants deter pests. Educate yourself on the permaculture principles behind this.