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Starting Spinach Indoors - Potting mix?

Posted by bella_trix z6b SE PA (My Page) on
Wed, Jan 7, 09 at 14:58

I typically use Premier's Pro-mix for starting all my seeds inside. It is absolutely fantastic for almost everything I grow. Except spinach. I can not start spinach indoors with the pro-mix. It germinates just fine in the garden, but barely (1/20) germinates inside.

I would like to get an early crop this year by starting inside. Can anyone recommend a potting soil that seems to work? I would prefer to avoid anything with miracle grow or potting soils with a wetting agent (polyacrylamide). Has anyone been successful starting spinach inside? Any tips?

I have been so successful seed starting everything else that this failure is really bugging me!

Thanks for any help,

Follow-Up Postings:

RE: Starting Spinach Indoors - Potting mix?

It's not the potting mix, I'll bet. I bet the mix is too warm. I've noticed spinach wants cool soil to sprout so try again with soil that's cooler and I'll bet they sprout.

RE: Starting Spinach Indoors - Potting mix?

I wondered about that. I've tried them both on and off heat. It's room temperature in the basement, plus the lights do add a little heat. Maybe you're right and it is just too warm. Where do you place your seed to germinate? I have an area that is about 50F. Maybe that would work better?

Great idea!

It's the temperature

I just found another thread on the Hydroponics forum that supports the not-cold-enough idea. Shebear - you were absolutely correct! For anyone else having trouble, the other thread has some great ideas on how to get better germination


Here is a link that might be useful: Spinach seeds not growing...

RE: Starting Spinach Indoors - Potting mix?

I figured this out this fall when we tired to start spinach in the community garden. We planted lettuce, radish, chard and spinach on the same day. Everything came up but the spinach had really poor germination rates. By the time, we had time to replant the crazy Texas weather had changed and we got cool weather. I planted thick hoping to get a decent bunch of plants. Well I think every seed made two plants. We had spinach coming out of our ears.

Have fun trying again.......Wishing you luck!

RE: Starting Spinach Indoors - Potting mix?

if it isn,t the temp. it is old seed .it needs to be fresh seed every year i garden in zone 4 and found this out the hard way

RE: Starting Spinach Indoors - Potting mix?

Here is my 2 cents since I am currently starting (already started) about 25 spinach plants indoors...

My first experience is I bought a 25 cent package of spinach seeds from Wal Mart...

I then made newspaper pots and put dirt in them from outside (just scraped some up from the old garden).

I had 1/20 that actually germinated.

Then I took the remainder of the same pack of seeds as above, got a sandwich bag and a wet paper towel, dumped the seeds in and tossed them in the window.

After about 10 days I had a number of seeds germinating inside the sandwich bag...which I transplanted one by one with tweezers to my previously made newspaper pots.

The germination rate was still low and staggered but after about 2 weeks I had all I needed for myself.

I did try to toss the sandwich bag in the fridge from time to time, but from observation the heat and cold from sitting right next to a window day and night was enough.

Now they are sprouted and I will set them out soon.

That is experiment #1.

My second experiment is that I bought a new name brand envelope of seeds. Instead of 25 cents, it cost me $2.

I also had about 20 pete pellets in one of those jiffy greenhouses left over. (I bought 2 X 72 count mini greenhouses and filled up almost everything with other stuff)

I put my new seeds in my left over pete pellets and let it go right beside my tomatoes.

In a matter of days I had sprouts...the germination rate was really high. So far 16/20 of my pete pellet spinaches are up and growing.

I will transplant them outside soon too.

RE: Starting Spinach Indoors - Potting mix?

How odd that this thread should pop back up now! I just finished with my spinach experiment and was thinking I should post the outcome.

I'm still not entirely sure that it is temp alone that gives me my trouble, but temperature definitely has something to do with it. Just to let you know, the seed that I tried starting indoors was not old. I have no problem growing spinach seed outdoors in the spring, even if the seed is up to 3 years old. My problem is starting indoors and growing in the fall.

Experiment #1
I was successful using the method that Alamo used. I placed the seed in a damp paper towel in a zip-lock bag and left it in the fridge for four days. Nothing happened. I then took the bag out of the fridge and set it in a cool part of the house. I actually forgot about it (whoops), so I'm not sure how many days went by, probably 3-4. 95% of the seeds had germinated. I individually planted each sprouted seed in my promix potting soil and they are very happy now.

Experiment #2:
I planted the same spinach seed directly in the promix and set it in an unheated, with a window, section of the house. It was most likely about 40-55 degrees. 13 days later only 5/13 seeds had germinated.

The paper towel method was a little more work than seeding directly in the pots, but not by much. And it works so much better! Now, if I can just get this to work for the fall. My real goal is not earlier spring spinach (which would be nice, but not necessary) but Fall spinach.


RE: Starting Spinach Indoors - Potting mix?


I am thinking the main differences is definitely climate.

You said you are having 40-55 degrees....Here we are getting up into the 60's and 70's lately on a pretty regular basis. At night it might hit the mid 40's, but usually its in the 50's.

I don't know, but its interesting... especially since this is my first time ever to grow spinach.


RE: Starting Spinach Indoors - Potting mix?

Actually, that section of the house stays 40-55 degrees. It's 29 degrees outside right now :(. I can only wish for 60s and 70s! Is it spring yet?


RE: Starting Spinach Indoors - Potting mix?

Spinach Folks: Check out the wintersowing forum. Spinach is excellent for WSing and can be done now. I planted out two containers a couple weeks ago (in the snow) and I've got great germination. Hard to beat WSing for the cool/cold crops.


RE: Starting Spinach Indoors - Potting mix?

This is quite odd for me to read as have trouble getting spinach to germinate in the garden. I tried in early and mid spring and even in early and late summer with poor results. I now have some growing in my basement that I use as cut and come again salads. I put mine into a rectangular container that is 3"x9" with potting mix from the store...simliar to miracle grow but off brand...anyway I then put them on top of the hot water tank. Every seed germinated...I wonder why now since it did get a little bottom heat. I really want spinach outside and may try the papertowel method and then plant into the soil...since I do sq ft garden method not a huge problem. Kim

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