If you don’t stock up on vegetables during home quarantine, can you support yourself by growing vegetables on the balcony?

Review expert: Wang Guoyi, Postdoctoral Fellow in Nutrition and Food Safety, China Agricultural University

The recent recurrence of the epidemic has rekindled the desire of many friends to "stock up". The topic of stockpiling has been discussed recently in the editor's circle of friends. Some hardcore ones have even been discussing how to transform their own balconies to achieve "vegetable freedom".

Friends in the group who are prepared for a rainy day have begun to develop their imaginations (the picture has been modified)

Source丨Editor

Of course, the possibility of hoarding a large amount of food to survive a crisis in real life is almost zero, but I believe many friends have imagined such a scenario: the end of the world is coming, and you hide at home alone, relying on the supplies you have stored in advance and the food and vegetables you grow at home to survive, and avoid the approaching crisis...

So, let's consider a more down-to-earth science fiction question: If the end of the world comes, can you feed yourself by growing crops and vegetables on the balcony?

Premise of making assumptions

Before we begin, it should be noted that the output and values ​​mentioned and calculated here are only rough estimates, and many details and aspects will not be 100% consistent with the actual situation. Let's study this issue with a sci-fi heart~

Okay, let’s start thinking.

Let’s first assume that the end of the world has come, and the outside world has suffered from serious pollution/radiation/infectious diseases/zombies... but the building of your home can provide you with very good protection, and you don’t have to worry about any harm while living at home - in short, you can’t go out.

Maybe the back of the earth was hit by a meteorite.

Source: Internet

Meanwhile, you have all the tools you need at home, as well as enough food to last you until your first harvest and unlimited water, because you can't grow enough food to eat overnight, no matter what you plant - unless you're in a video game.

Our core question is: How much food do we need to grow to feed one person?

How much does a person eat in a day?

So the question is: how many nutrients does a person need in a day to sustain life? The recommended daily nutrient composition table for adults aged 40-50 years old that we found on Wikipedia and other information websites is as follows.

Source: Wikipedia

The data obtained by combining other reference materials are as follows:

The recommended daily intake of foods for adult men is:

300 grams of staple foods such as cereals; 400 grams of vegetables; 300 grams of fruits; 150 grams of meat, poultry, fish and shrimp; 50 grams of eggs; 40 grams of beans and bean products; 300 grams of milk and dairy products; 25 grams of oil.

The recommended daily intake of foods for adult women is:

250 grams of staple foods such as cereals; 300 grams of vegetables; 200 grams of fruits; 100 grams of meat, poultry, fish and shrimp; 25 grams of eggs; 40 grams of beans and bean products; 300 grams of milk and dairy products; 25 grams of oil.

It is obviously difficult to maintain the most appropriate nutritional intake under the conditions of doomsday. After all, the conditions are limited, and farmed meat, eggs, aquatic products and long-term cultivated fruits are obviously out of the question. We simply simplify the problem to only eat staple food and vegetables, and lower the standard a bit, that is, 250 grams of grain per person per day.

What to plant? How to plant?

Planting corn, rice or wheat on the balcony obviously cannot meet the food needs. In order to find the staple food suitable for planting on the balcony, we checked some information and found two more reliable options: sweet potato (Ipomoea batatas) and potato (Solanum tuberosum).

Sweet potatoes and potatoes Source: Internet

Overall, these two have all the elements to provide nutrition for people in the end times - complete nutrition, sufficient energy, easy to cultivate, and considerable yield...

However, after comprehensive consideration, we still recommend that you choose sweet potatoes as your staple food during the end of the world.

Compared with potatoes, sweet potatoes have several advantages that are hard to ignore: first, the sugar content of sweet potatoes is higher than that of potatoes, which can provide more energy in the case of food shortage; second, in addition to the tubers, the stems of sweet potatoes also contain starch, which can be used as emergency food when food is insufficient; third, the stems and leaves of sweet potatoes can be eaten, which is a kind of green leafy vegetable in itself, which can supplement the lack of vitamin C to a certain extent; finally, potatoes in storage are prone to sprout, and potato sprouts are poisonous, so they are not conducive to storage.

Sweet potato seedlings planted in pots Source: Wikipedia

Now that we have decided on the type of crop, we have already mentioned that there is enough water, and assuming that you like gardening, have enough growing substrate at home, and have a device in your storage room that can produce fertilizer from human daily metabolic waste (a composting tank), we can now start growing sweet potatoes.

How much to plant? How long to harvest?

The next question is more practical: How many sweet potatoes should you grow to meet your daily food needs?

Unfortunately, we did not find the yield data of sweet potatoes grown in home gardens, so we quoted the average yield of sweet potatoes per mu mentioned in the press release of the Ministry of Agriculture and Rural Affairs (about 3,000 kg per mu) as a parameter for an irresponsible and rough calculation. Considering that it is difficult for your balcony to achieve the optimal planting effect, we will discount the yield of sweet potatoes per mu and say it is 2,000 kg/mu.

A good harvest of sweet potatoes can indeed give people a sense of satisfaction.

Source: Internet

After consulting with agricultural practitioners, we roughly concluded that the harvest period of sweet potatoes is 120 days. One acre of land is about 666.67 square meters, so the yield per acre divided by the area and then divided by the number of days in the harvest period is roughly the number of sweet potatoes grown per square meter of planting area in your balcony vegetable garden every day.

Taking out the calculator on our phone, we get a value of about 25 grams, which seems far from enough to feed an adult. But in other words, as long as the planting area is expanded to 10 square meters, it will just be enough to meet the needs of one person.

The problem is that a 10 square meter balcony (plantable area) is a bit difficult for most houses.

Source: A shopping website

Fortunately, we found this kind of stackable planting boxes. The area of ​​each box is about 0.16 square meters (40 cm * 40 cm). If we calculate it as a set of three layers, the planting area of ​​each set is about 0.48 square meters. That is to say, you need more than 20 sets of planting boxes on your balcony. Considering the light exposure, a 5 square meter balcony with plenty of sunshine should be enough for you to place so many planting boxes.

If you do some calculations, if you harvest once every 120 days, it will just be enough to meet your daily food needs. Considering that sweet potatoes can be dug and eaten anytime, our food reserves can be even more abundant.

Do you want to improve your life?

With sweet potatoes as a stable food source, we can also improve our lives. Eating sweet potatoes all the time will make life boring (maybe not completely boring, think about what changes will happen to your digestive tract if you only eat sweet potatoes for a long time).

Assuming you have an uneaten oyster mushroom (Pleurotus ostreatus) in your refrigerator and a pressure cooker in the kitchen that can be used for high-temperature sterilization, we can also make a fungal culture medium using dried sweet potato stems, leaves, waste paper and other materials.

Source of wild oyster mushrooms丨Wikipedia

That’s right, there are mushrooms to eat.

Source: Food World

Compared to sweet potatoes, mushrooms provide more nutrients. More importantly, mushrooms do not need sunlight to grow, and you can grow them anywhere in your home with suitable temperature and humidity.

Staple foods, green vegetables (sweet potato leaves) and fungi, now your food source can be said to be both healthy and stable, at least enough to keep you going until rescue arrives or the crisis is over.

Wait, you said you still want to get animal protein?

It is not impossible. Small animals that grow fast, reproduce fast and are rich in protein are easy to obtain - it's just that most people find it difficult to accept their sources psychologically - just think about the food rations people have in those doomsday movies!

Source: Screenshot of a game