The zombies have come and gone,

and all plant life on Earth has died somehow.

All you have are some basic supplies

and some seeds of a few types of essential plants.

So, what should you do

to make absolutely sure they grow,

seeing how rebuilding human civilization

absolutely depends on it?

Well, you'd probably think

the last thing you should do

with these crucially important seeds

is something like poking holes in them,

or grinding them with sandpaper,

or throwing them in acid

or hot water.

But, in fact, all of these are methods

that are commonly used

to help seeds start growing.

A typical seed consists of a plant embryo

encased in a hard seed coat.

To start growing,

it needs to emerge or sprout

from inside this shell.

This process is called germination.

But just as it would be hard

for you to get out of a jail cell

with no windows and no doors,

the embryo might need a little help

escaping from its seed prison,

and any process that makes this easier

by wearing down the seed coat

is called scarification.

This lets moisture and nutrients

get through the seed coat,

making the embryo start growing

until it breaks through.

Now, you might be wondering

why it is that plants would need humans

to do all these weird things to their seeds

in order to grow,

and, in fact, they don't.

In natural environments,

seed coats are worn down by cold temperatures,

bacteria,

or even animal digestion.

Our scarification methods just mimick

and accelerate these natural processes

to increase the chances of successful germination.

One technique we can use is called nicking.

To do this, we make a small cut or scratch

into the seed coat.

Be careful not to cut too deep!

You don't want to damage the plant embryo inside.

Another way is to file down the seed coat

using sandpaper or a nail file.

Once again, you don't want to file too much,

just enough to wear down some of the seed coat.

After applying either of these methods,

you'll want to spray the seeds with bleach

to prevent mold.

Seeds can also be soaked in water

to soften the coat.

One way to do this

is to place the seeds in a nylon bag,

then place the bag into hot water.

Turn off the heat immediately

and allow the water to cool to room temperature

before removing the seeds.

It's important not to heat the seed for too long

as this will kill the embryo.

Again, you'll want to spray them

with bleach afterwards.

Finally, you can try immersing the seeds

in a sulfuric acid solution.

Make sure you're wearing protective goggles and gloves

any time you work with such a dangerous substance.

Place the seeds into a wire mesh pouch

and immerse the pouch in the solution for ten minutes.

Then take out the pouch

and rinse it with clean water.

Take out the seeds and, as before,

spray them with bleach so they don't get moldy.

If you try all of these methods,

you will see that some of them

are more effective than others,

and some work best for different types of plants

that have harder or thicker coats.

So, knowing what seed scarification techniques work best

will be useful if you ever need to survive a cataclysm,

start a farm,

or just want to plant in your own garden.