My reference to follow, shows how dangerous and destructive fire can be to a farmer’s crop... especially to a grass crop, like wheat.  

In Bible times, such a fire would be devastating.

I was reading an article on the Russian wheat crisis a while back.  It appears that a significant portion of the wheat harvest (up to one third) had been destroyed, much of it due to drought and fire.

Russia stopped exports due to this loss. Russia supplies much of the wheat for the world. Economists say the price of wheat will increase significantly.

What if the fire was worse and more widespread?

     You might wonder what does this subject on the Russian Wheat Harvest disaster have to do with the Bible subject, of when the "weeds" get burned?  
(Mt 13:30, 40)

Some people mistakenly think that the weeds are burned up first...before the wheat is gathered up.  The bible does not say that.

Since fire can easily get out of control and destroy a wheat harvest, then it may very well help us to see when the "Weeds" of Jesus' harvest illustration, actually get burned up.

This Russian "burning wheat" disaster reminded me of the "wheat or weeds" article listed in my articles.
 wheatorweeds-obadiah.blogspot.com 

I covered the "wheat" and "weeds" illustration, up to the "winnowing" process,  but I didn't cover what happens to the weeds. I just thought as most of us do, they get burned up. Does it really matter when? 
Well apparently, it does.         

Let's look at this:

The Bible doesn't say to burn them first...only to collect them first and bundle them for burning, or to be burned, set apart for burning.  Many translations and commentators agree with this...

Scofield reference notes:

The gathering of the tares into bundles for burning does not imply immediate judgment. 
At the end of this age (Mt 13:40) the tares are …set apart for… burning, but first the wheat is gathered into the barn.

New International version:

"Let both grow together until the harvest. At that time I will tell the harvesters: First collect the weeds and tie them in bundles…to be burned; then gather the wheat and bring it into my barn"

International Standard version:

Let both grow together until the harvest and at harvest time I will tell the reapers, "Gather the weeds first and tie them in bundles… for burning, but bring the wheat into my barn."'"

   Now before you bring the wheat into the barn you need to prepare it.

You need to collect the wheat and bring it to the threshing floor to thresh it out.  Then you need to winnow it.
Let's start with this "winnowing" process of harvesting wheat and then lead up to the burning of the chaff.
(There are some great pictures and stories of winnowing on the Internet).

In the simplest form, winnowing includes throwing the threshed mixture into the air so that the wind would blow away the chaff.

There was a rough winnowing with a pitchfork, which got rid of the larger pieces of waste.

Next there was a finer winnowing of the grains with a hand held very large "pan" or a "fan".

The farmer would throw the grain up into the air many times, often up to several feet high. The grain would gradually become cleaner with each toss as the strong wind blew through it, removing all the remaining chaff.

This can be likened to a refining process (Cleansing it).

The Threshing floor was usually located in an area that was very windy and at a higher elevation.

Interestingly the Hebrew word for wind is "ruach" which also is used for "God's spirit".

Now the harvest is a very time consuming, and exhausting endeavor.

Sometimes farmers had to move quickly if the rain threatened their crop. (For example if a storm was coming). Today many farmers also try to get their crops, especially "grass crops", like wheat and feed hay harvested quickly while they are dry and ready.

This would be a priority to get wheat, "threshed, winnowed, and stored safely into the barn or the (storehouses).

If these crops get wet, molds will grow, and the crop will be ruined. This damage would be costly. (Today many farmers cover hay bales with plastic to keep the hay from getting wet.)

2000 years ago, everything was done by hand, and there were no weather reports, which made it even more important not to waste time during the harvest.

(The weeds would have been already removed from the field and "bundled" before being set on the side).

(But they were not burned immediately. To do so would also endanger the standing wheat.)

        Since the farmer is working laboriously by hand, and often against time, it would be wise not to waste time and energy burning "valueless weeds" when his wheat needs to be harvested.

The wheat needs to be cut down with a sickle by hand, threshed out, winnowed by hand several times and then the cleansed grain is gathered into the storehouse.

To burn the weeds right away was not a safe thing or economical thing to do.

The dry ripe wheat crop was still standing and therefore vulnerable to catching fire and being totally destroyed.

No farmer in his right mind would want a fire blazing anywhere near his precious wheat.

 Look at the recent damage to the Russian wheat harvest. Then too look at the vast damage from the many wild fires that yearly rage out of control in the western United States.

Any Hebrew child would remember the story of Samson and the 300 foxes that he sent through the dry, ripe, standing wheat fields of the Philistines, with flaming torches tied to their tails.
(Judges 15:4-5)

Let us also consider why the weeds were "bundled" at all, if they were only going to burn them?

Although wood was also used for fuel, it was too costly and valuable. It was not something that many poor people could afford to use. They did not have the luxury to "waste" wood as a common bulk fuel. These cheap weeds could be bundled tightly into little "weed bundles" and used as fuel to cook with.
The "bundled" weeds of course (in those days) would serve as a needed winter fuel source. 
Of course Jesus' listeners would know this. 
Without research, most modern people don't know these things.

See footnote:  In days past, the Native Americans and pioneers, also used weed bundles – the pioneers called these weed bundles "hay twists".  (These were cheap readily available sources of fuel for cooking and keeping warm.)
They also used  Buffalo Chips and Cow pies (Dried Dung)  
It was quite cold out there on the plains out west. (Wide open spaces in places like Nebraska, Oklahoma etc, did not have as many trees as some states do…( wood was scarce and valuable).  I read a lot about it in some "letters" from the old west days on the Internet. 

So with the wheat cleansed and safely stored in his storehouse, the farmer could then direct his attention to the "clean-up" of the useless chaff and burn it, or more likely, save it for fuel to be burned later.

I think,  the wheat getting gathered into his storehouse, refers to the anointed "wheat" being refined and sealed...(gathered, threshed, and winnowed...cleansed). (Mal 3:2, 3) (Mt 3:12) Two thousand years ago, Jesus said that the fields were already ripe for harvesting. (John 4:35)  Anointed were being gathered into the storehouse all along since the Apostles.
   

 Once the precious wheat is safely gathered into the storehouses, the burning of the chaff and weeds can be dealt with.

According to the Bible, the distinction and segregating is already made between the wheat and weeds, prior to any destruction by fire.  The harvester commands that the weeds be segregated and bound in bundles to be burned at a future time. Just as the faithful are gathered into the storehouse by the end of their lives (Or the end of this system), the unfaithful are made manifest and bundled by the end of their lives.  
(Mal 3:18) (2 Tim 3:13) (Matt 13:30) 
(2Pet 3:10) This fire is not literal.
Why by the end of their lives?   Because as Ecclesiates says the day of a man's death is better than his birth.  By that time he proves what he is. (Ec 7:1) 

Agape, Obadiah.

"Food for thought"

Additional notes:

In days past, the Native Americans and pioneers, also used weed bundles – the pioneers called these weed bundles "hay twists".  (These were cheap readily available sources of fuel for cooking and keeping warm.)
They also used  Buffalo Chips and Cow pies (Dried Dung) 

I read a lot about it in some "letters" from the old west days on the Internet.   If you are interested look up Buffalo chips or Cow pies. 
This scarcity of wood is also the reality in the Middle East (where Jesus' illustration took place).

 The old west articles were very interesting.

I thought some might be interested to know that even mankind today is looking to make fuel out of "weeds".

Bio-fuels are different because they put it in a liquid form. The military is looking at jet fuel made from weeds, animal fat and such.

In some countries they are using aquatic weeds for bio-fuel, just like corn is used. They are also looking at "switch grass" for making fuel.

You can buy "Peat logs" from Ireland.  Peat logs are basically (Naturally) decomposed & compressed vegetation/moss/weeds/grass etc. (whatever was there on the bogs.) You can buy them 25 logs in a box on line. They are very efficient for heat. The Irish don't have a lot of wood for fuel either. The English cut down most of the trees to build their ships years ago.

So even today, fuel sources like “weeds” are used.  

I just thought this was interesting.
Obadiah