From the comments:
Joe could you do an article about best seeds for a bad times garden? And why.
This kind of post is really more of a starting point for conversations rather than anything definitive. There are just too many variables in gardening and too many permutations in what kinds of food resources might be available.
All comments are welcome. Please feel free to join the food-fight!
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Historically, governments make a stab at supplying carbohydrates to starving populations. Typically, they will subsidize the cheapest form of calories and they might supply vitamin pills to pregnant women and children.
The downside is that goons and thugs will add "taxes" and "protection costs" to the products. Nevertheless, I am going to start with the assumption that it will be possible to buy tortillas and white rice through the entire "event". Both keep very well without refrigeration and do not need to be handled gently. They may be rationed (perhaps five-to-eight ounces a day, per person) with the government expecting local industry to supply the remainder of the needs.
Because of the gangland aspect, actual availability will be spotty. Rural areas will probably be out-of-luck with regard to access, but in their favor, rural areas will have more land-area for food growing.
But for the sake of this post, let's assume that you live within 10 miles of a city of 5000 or more people (an hour's ride by bike) and will have some access to tortillas.
The DO NOT GROW plants:
Don't grow pumpkins. They are vandal magnets even today. Modern pumpkin varieties turn to tasteless mush when cooked. Instead, grow winter squash with dingy, outside coloring. Butternut types (C. moschata) has the highest beta carotene content of the commonly available squash is C. moschatas are relatively disease and insect resistant. Waltham's Butternut is a very solid choice.
Don't grow sweet corn. It is empty calories. Both sweet corn and pumpkins can use a lot of area. FIELD corn is a possibility to supply brute calories as a hedge against the supply of burritos being cut off. Have a plan to kill-and-eat every raccoon that even thinks about setting foot on your property. The "and-eat" means that poisons are not an option.
Do not grow little fiddly, high-labor plants with high outside-input requirements. Micro-greens grown in hydroponics will fall in this category unless you live in Alaska.
DO GROW
Focus on vitamins. Then protein. Then fats. That all changes if the tortilla-pipeline crashes, but that is where I choose to start.
#1 Turnips/rutabagas: They self-seed so it can be a perpetual plant. Purple-top turnip is the most common variety and is just fine. Both species self-seed. Both species have edible greens that you can brush the snow off-of, cook and eat. These are listed first because if you it is a triple-play of vitamins (especially in the greens), calories and fiber. They store very easily. They can over-winter in the garden.
If you don't like the taste, it is because you aren't hungry, yet.
Runners-up
Savoy Cabbage (Deadon (H) or January King (OP)). I find that the red cabbage are less bothered by cabbage worms.
Daikon Radishes (I favor the stumpy, Korean types. Green Luobo is an open-pollinated variety. Hybrid seed is much easier to find.
#2 Beans: I expect a lot of hate on this, but soybeans are both a protein and a fat play. Most soybeans are geneticially modified, so if that is important to you then use (sprouting) soybeans purchased at an Asian food store.
Runners-up
Almost any green bean released after 1950 will have multiple disease resistances. A major consideration is having a "bush" stout enough to hold up all of the beans off the ground.
Pole beans are great if you have ready-made structures like cattle panels or want to try Three-Sisters agriculture. Musica was the most vigorous for us this year. With regards to Three-Sisters, the rambling squash vines tend to short-out electric fences which complicates protecting corn from raccoons. It might not be worth the potential losses to multi-crop depending on your local raccoon population.
Dry-bean specific varieties...the easiest path is to go to Walmart and buy a pound of small red beans or pinto beans and plant a row of them.
Cowpeas. Find an old gardener in your area and ask him/her what varieties do well for them.
#3 Sunflowers: It is very hard to find a robust, vegetable source of fats other than nuts (and raccoons). Sunflowers have a broad range of adaptability. The best oil varieties are not available to home growers EXCEPT as bird seeds. So I am going to recommend that you consider planting black-oiler bird-seed. Obviously, they will be a magnet for damage so keep an eagle eye on them and as soon as the birds start hitting them, cut them and hang them upside down from the rafters in your garage to dry.
If planting bird-seed makes you puke, Johnny's Seeds offers a variety called Royal Hybrid 1121.
Runner-up
Canola (if you can find seeds)
Peanuts (if you have sandy soil and a very long growing season)
#4 Potatoes: Brute calorie play, surprising amount of vitamin C and fairly well balanced protein. Unlike pumpkins or corn, nobody is going to sneak up in the dead-of-night and rip-off your entire harvest. Varieties can be fussy about what sites they like best so the best bet is to talk to the old-timers or plant a partial row of the three-to-five varieties that seem promising and have a horse-race.
One consideration that is often overlooked is that potatoes have a lot of water in them. One variety might seem to yield fifty percent more potatoes yet, in fact, have provided more water but fewer calories. Potatoes that bake (or microwave) "dry" have more starch and protein in them per pound than potatoes that cook up "waxy". Don't waste precious storage space on "water".
#5 Cucumbers: Any cucumber variety released after 1950 is likely to have multiple disease resistances. The no-brainer play is to pick a hybrid of the kinds you like and to have some open pollinated varieties as back-up. Seeds from hybrids will show a lot of variation and will show some resegregation in terms of disease resistance. That is, each plant will not have the entire disease resistance package the hybrid advertised. But in many cases, the f2 hybrids will produce pretty nice cukes and you might be hard-pressed to find open-pollinated, Japanese cucumbers (for instance).
Cucumbers edge out tomatoes for #5 because pickling is a low-energy way to preserve and as a low-temperature process preserves more of the vitamin C.
H-19 Little Leaf and Wautoma look like solid pickling cucumber choices.
#6 Tomatoes: Stupice continues to star in our garden. It is very early and is just barely big enough to be worth picking. It is open pollinated.
Ace 55, Rutgers and Siletz are open-pollinated and have some resistance to Fusarium or verticillium wilt.
The same comments about planting hybrid seeds I wrote in "cucumbers" applies to tomatoes.
#7 Carrots: Short, stumpy varieties are easier to grow. This is primarily a vitamin play (beta carotene). The deeper orange varieties are better. Seed vigor is always a challenge with carrots.
Those are the heavy-lifters. You can plant a lot more kinds of vegetable-garden plants but the selections shown above put players on most of the important squares.
Numbers 2 and 3 are negotiable if dried beans and fats/oils are readily available.
Flavor plants
Onions and garlic
Multiplier onions are an easy choice and can be tucked into odd corners. Green onions are a fast way to grow flavor for those burrito-wraps.
"Porcelain" and "Stripe" type garlics are very long-keeping and cold-hardy while Racambole types are less-so. "Stripes" are usually easy to peel.
Peppers: Cayenne offers a lot of heat per-square-foot and is mild enough to be easy to work with...but wear rubber gloves when cutting it. It is also thin-walled which makes it fast-drying, a big factor in places with wet, rainy autumns.
Mint: Lots of choices. Catnip often volunteers near foundations. It seems to like concrete (calcium and higher pH, probably).
Wild foods: Nuts are a great fats/oils play if you can collect them in enough quantity. Black walnuts and hickory nuts are pretty common. If your local hickory nuts are tiny or refuse to let go of the meats, the oil can be extracted by pulverizing the nuts and boiling them and skimming off the oil from the top of the "soup".
Most greens don't have enough calories to keep you alive but do have flavor (sometimes too much) and vitamins.
Daylilies, all parts are edible.
Addendum One:
Addendum 2
The institutional memory of the research and breeding community made the 1950s as the golden era of home-gardening variety releases.
The Great Depression and the blockades and Victory Gardens of WWII were still on everybody's minds. Research projects that launched in the early 1940s were coming to fruition in the 1950s. Later research turned to commercial farming and having all of the fruit ripen at one time and making it tough enough to ship.
Even today, hybrid sweet corn like Iochief and Sweet G90 have a cult following.