Heat Treatment Delays, Doesn't Reduce Germination?

Nan_PA_6b · July 28, 2017

Previous studies have shown that heat-treating tomato seeds at 122F for 25 minutes will destroy diseases inside the seeds, but also reduces germination percentage.

I own a sous vide' machine, which holds a circulating water bath at a precise temperature. I wanted to see how badly germination would be reduced after heat-treating seeds.

I cleaned a batch of Hardin's Miniature tomato seeds by the Oxiclean method. After they had dried for 4 days, I separated the seeds into 2 batches. One batch received no treatment, the other received a heat treatment in a sous vide' bath. The heat treatment seeds were put into an organza bag, and put into a hot water bath at precisely 122 degrees F for precisely 25 minutes. The wet seeds were allowed to dry for about 4 hours.

Then, 17 seeds of each batch were planted, one seed per cell, in a seed starter tray, in the same medium. 17 seeds was the chosen number because the starter tray rows were 17 cells long.

Here are the germination results:

Day___ heat batch____ no heat batch
7_____ 10_____________ 0
8_____ 11_____________ 0
10____ 12_____________ 2
13____ 15_____________ 6
19____ 15____________ 13
20____ 15____________ 15

The results suggest I mislabeled the rows, so the heat-treated was labeled "no heat" and vice versa. But either way, the germination rate for both heat-treated and non-heat-treated seeds was 15/17= 88%.

One of the batches reached full germination in 13 days, the other in 20 days. If the heat treated was actually the batch that was slow to germinate, previous studies may have not gone on long enough to notice the late germination. They would conclude that germination was reduced.

My results suggest that I can heat treat my seeds and get decent germination. Germination testing will be difficult, as it will take about 3 weeks. I don't know if one can germ test in a wet paper towel for three weeks?

So, if you were to receive seeds from me, would you prefer to have heat-treated, slower to germinate seeds, or not heat-treated, quicker to germinate seeds?

Discuss...
Nan

JRinPA · July 29, 2017

I think you need to re-run the test to confirm the results. I would want the ones that germinate quicker.

Worth1 · July 29, 2017

Re run the test with fermented seeds and OXI Clean both of which would then be treated in the water and not treated in the water bath.
I have a reason for this I will explain.
I have received seeds from people that have had all sorts of things done to them or I dont know what they did.
I have received seeds from Carolyn not on her seed offer that were way old big time.
I know how Carolyn does her seeds.
Her way old seeds were at almost 100% germination and they came up fast.
Seeds from other folks were either zero almost zero or took forever and a day to germinate.
No I am not doing anything wrong I know how to grow tomatoes from seed.

Your question?
I dont want any seed that takes 1/2 a month or more to germinate.
It would throw off my timing with plant out and create difficulty in my light setup.

Gerardo · July 29, 2017

heat treated please, as you own the gear to do it in a convenient way. Thanks for sharing results.

Nan_PA_6b · July 29, 2017

Quote:

Originally Posted by JRinPA

I think you need to re-run the test to confirm the results. I would want the ones that germinate quicker.

I think you're right about re-running the test to confirm that it is actually the heat-treated ones that were slower.

Also, since it took 13 days for all of the quicker ones to germinate (which is long), I want to try a germ test on a heat mat to see if that quickens things up. The room temperature in this experiment was 72 F.

Nan

Douglas_OW · July 29, 2017

Nan,

If you do run another test, consider allowing both samples to dry thoroughly (~30 days or more) before attempting germination. I have no idea if this will help or hurt germination, but it is a more realistic test. I don't think anyone is going to plant seeds just hours after they have been processed, not even yourself.
I realize that this is easy for me to suggest, but you did ask for discussion.

Jim

Quote:

Originally Posted by Nan_PA_6b

I think you're right about re-running the test to confirm that it is actually the heat-treated ones that were slower.

Also, since it took 13 days for all of the quicker ones to germinate (which is long), I want to try a germ test on a heat mat to see if that quickens things up. The room temperature in this experiment was 72 F.

Nan

Nan_PA_6b · July 29, 2017

Quote:

Originally Posted by Douglas_OW

Nan,

If you do run another test, consider allowing both samples to dry thoroughly (~30 days or more) before attempting germination. I have no idea if this will help or hurt germination, but it is a more realistic test. I don't think anyone is going to plant seeds just hours after they have been processed, not even yourself.
I realize that this is easy for me to suggest, but you did ask for discussion.

Jim

I agree; I also wondered what effect the (moist vs. dry) had on the seeds.

The leftover seed has all been sitting dry since the heat treatment, so that won't be a problem. Thanks!

Nan

**carolyn137** · July 29, 2017

Nan,which specific diseases are you trying to prevent that are found in the seeds, and I ask since I've posted about this many times before, as a search here will show.

The most common tomato diseases worldwid are the two Fungal ones of Early Blight which can occur early or late in the season, and Septoria Leaf Spot, and the two bacterial ones of Bacterial Speck and Spot. .

Those can usually be removed by effective fermentation of seeds

So what pathogens are inside the seeds in the embryo?

Various viruses,not all,but those that have been tested plus
Potato Spindle virus,which also infects tomatoes,
Viroids, and another one I can't remember now.

Some prefer to use oxidative methods to remove pathogens on the outside,but we've been through this many times and it has been shown NOT to be effective for TOMATOES, but pine cone seeds and some others.

I see Worth has put up a new thread about fermentation,but I probably won't post there,just noting that is does much more than just removing pathogens from the exterior,it also removes the gel capsules around each seed, which is very good IMO.

For sure heat treatment can lower seed germination and if I had time I'd do a search here which showed which heat methods kept temps stable long enough to at least get some seeds that might be pathogen free.

If you look in some of the larger seed catalogs, or a commercial version separate from the home garden one you'll see that some of them offer heat treated seed and ask more money for that.

Carolyn

Worth1 · July 29, 2017

Quote:

Originally Posted by carolyn137

I see Worth has put up a new thread about fermentation,but I probably won't post there,just noting that is does much more than just removing pathogens from the exterior,it also removes the gel capsules around each seed, which is very good IMO.
Carolyn

I'm heart broken.

I would hope you would chime in as it is about fermenting and nothing else but fermenting seeds.

Worth

**carolyn137** · July 29, 2017

Quote:

Originally Posted by Worth1

I'm heart broken.

I would hope you would chime in as it is about fermenting and nothing else but fermenting seeds.

Worth

I did look quickly a day or so ago and saw that someone said they did fermentation the same way I did.

Was that you who posted that?

Carolyn

Nan_PA_6b · July 29, 2017

Carolyn, do you think heat treatment would be likely to kill off pathogens on the seed surface as well?

Nan

salix · July 30, 2017

Nan, glad you started this experiment. I suggested many years ago that a sous vide set-up would enable such a process. I would echo Doug's comment above, re: testing the heat treated seeds again. Perhaps in a year. It strikes me that the heat treatment may not prevent germination per se, but may shorten the seeds viable life.

Actually, I may have made that suggestion over at SSE many years ago and not here...

Nan_PA_6b · July 30, 2017

Quote:

Originally Posted by salix

Nan, glad you started this experiment. I suggested many years ago that a sous vide set-up would enable such a process. I would echo Doug's comment above, re: testing the heat treated seeds again. Perhaps in a year. It strikes me that the heat treatment may not prevent germination per se, but may shorten the seeds viable life.

Actually, I may have made that suggestion over at SSE many years ago and not here...

That's a good idea, testing heat-treated seeds over time to see if shelf-life is shortened.

Tonight I potted up the 15 biggest seedlings. Luckily, they are miniature plants.

Nan

AlittleSalt · July 30, 2017

Quote:

Originally Posted by carolyn137

I did look quickly a day or so ago and saw that someone said they did fermentation the same way I did.

Was that you who posted that?

Carolyn

No, it was me. You already know I think you walk on water even though you pretend I don't listen :

**carolyn137** · July 30, 2017

Quote:

Originally Posted by AlittleSalt

No, it was me. You already know I think you walk on water even though you pretend I don't listen :

No, it was Worth.

(I have received seeds from Carolyn not on her seed offer that were way old big time.
I know how Carolyn does her seeds.
Her way old seeds were at almost 100% germination and they came up fast.
Seeds from other folks were either zero almost zero or took forever and a day to germinate.
No I am not doing anything wrong I know how to grow tomatoes from seed.)

Carolyn

July 28, 2017	#1
Nan_PA_6b Tomatovillian™ Join Date: Dec 2016 Location: Pittsburgh, PA Posts: 3,194	Heat Treatment Delays, Doesn't Reduce Germination? Previous studies have shown that heat-treating tomato seeds at 122F for 25 minutes will destroy diseases inside the seeds, but also reduces germination percentage. I own a sous vide' machine, which holds a circulating water bath at a precise temperature. I wanted to see how badly germination would be reduced after heat-treating seeds. I cleaned a batch of Hardin's Miniature tomato seeds by the Oxiclean method. After they had dried for 4 days, I separated the seeds into 2 batches. One batch received no treatment, the other received a heat treatment in a sous vide' bath. The heat treatment seeds were put into an organza bag, and put into a hot water bath at precisely 122 degrees F for precisely 25 minutes. The wet seeds were allowed to dry for about 4 hours. Then, 17 seeds of each batch were planted, one seed per cell, in a seed starter tray, in the same medium. 17 seeds was the chosen number because the starter tray rows were 17 cells long. Here are the germination results: Day___ heat batch____ no heat batch 7_____ 10_____________ 0 8_____ 11_____________ 0 10____ 12_____________ 2 13____ 15_____________ 6 19____ 15____________ 13 20____ 15____________ 15 The results suggest I mislabeled the rows, so the heat-treated was labeled "no heat" and vice versa. But either way, the germination rate for both heat-treated and non-heat-treated seeds was 15/17= 88%. One of the batches reached full germination in 13 days, the other in 20 days. If the heat treated was actually the batch that was slow to germinate, previous studies may have not gone on long enough to notice the late germination. They would conclude that germination was reduced. My results suggest that I can heat treat my seeds and get decent germination. Germination testing will be difficult, as it will take about 3 weeks. I don't know if one can germ test in a wet paper towel for three weeks? So, if you were to receive seeds from me, would you prefer to have heat-treated, slower to germinate seeds, or not heat-treated, quicker to germinate seeds? Discuss... Nan Last edited by Nan_PA_6b; July 30, 2017 at 08:40 PM. Reason: had the time wrong

July 29, 2017	#8
carolyn137 Moderator Emeritus Join Date: Jan 2006 Location: Upstate NY, zone 4b/5a Posts: 21,169	Nan,which specific diseases are you trying to prevent that are found in the seeds, and I ask since I've posted about this many times before, as a search here will show. The most common tomato diseases worldwid are the two Fungal ones of Early Blight which can occur early or late in the season, and Septoria Leaf Spot, and the two bacterial ones of Bacterial Speck and Spot. . Those can usually be removed by effective fermentation of seeds So what pathogens are inside the seeds in the embryo? Various viruses,not all,but those that have been tested plus Potato Spindle virus,which also infects tomatoes, Viroids, and another one I can't remember now. Some prefer to use oxidative methods to remove pathogens on the outside,but we've been through this many times and it has been shown NOT to be effective for TOMATOES, but pine cone seeds and some others. I see Worth has put up a new thread about fermentation,but I probably won't post there,just noting that is does much more than just removing pathogens from the exterior,it also removes the gel capsules around each seed, which is very good IMO. For sure heat treatment can lower seed germination and if I had time I'd do a search here which showed which heat methods kept temps stable long enough to at least get some seeds that might be pathogen free. If you look in some of the larger seed catalogs, or a commercial version separate from the home garden one you'll see that some of them offer heat treated seed and ask more money for that. Carolyn __________________ Carolyn

July 30, 2017	#12
salix Tomatovillian™ Join Date: Dec 2007 Location: north central B.C. Posts: 2,310	Nan, glad you started this experiment. I suggested many years ago that a sous vide set-up would enable such a process. I would echo Doug's comment above, re: testing the heat treated seeds again. Perhaps in a year. It strikes me that the heat treatment may not prevent germination per se, but may shorten the seeds viable life. Actually, I may have made that suggestion over at SSE many years ago and not here... __________________ "He who has a library and a garden wants for nothing." -Cicero Last edited by salix; July 30, 2017 at 02:11 AM. Reason: added thought

July 29, 2017	#2
JRinPA Tomatovillian™ Join Date: Jul 2013 Location: SE PA Posts: 972	I think you need to re-run the test to confirm the results. I would want the ones that germinate quicker.

July 29, 2017	#3
Worth1 Tomatovillian™ Join Date: Feb 2006 Location: Den of Drunken Fools Posts: 38,539	Re run the test with fermented seeds and OXI Clean both of which would then be treated in the water and not treated in the water bath. I have a reason for this I will explain. I have received seeds from people that have had all sorts of things done to them or I dont know what they did. I have received seeds from Carolyn not on her seed offer that were way old big time. I know how Carolyn does her seeds. Her way old seeds were at almost 100% germination and they came up fast. Seeds from other folks were either zero almost zero or took forever and a day to germinate. No I am not doing anything wrong I know how to grow tomatoes from seed. Your question? I dont want any seed that takes 1/2 a month or more to germinate. It would throw off my timing with plant out and create difficulty in my light setup.

July 29, 2017	#4
Gerardo Tomatovillian™ Join Date: Feb 2015 Location: San Diego-Tijuana Posts: 2,598	heat treated please, as you own the gear to do it in a convenient way. Thanks for sharing results.