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What are the advantages/disadvantages to starting seeds in say 4" pots or even 6" pots if that is what they are going to end up in anyway? I just completed my first up-pot of 100 plants and my goodness what a chore. I just want to know the answer because I know there are very good reasons there are a gazillion people on here up-pot sometimes multiple times instead of starting in a bigger pot.

Thanks..

Reason 1) It saves space to start them in smaller pots or community pots/seed flats.

Reason 2) If you need to heat the soil beneath the pots, it's MUCH easier to find the space to sit those smaller pots and put heating mats underneath them than it is 4" or 6" pots.

Cynthia H.
Sunset Zone 17, USDA Zone 9

Reason 3) instead of having 1/4-1/2 inch of stem base putting out roots (from seed depth) you get much more root origin after repotting the seedlings deeper. You could start by planting in half full drink cups and then adding more mix, but I have found that it is easier to put a plant in a hole than it is to put dirt around the plant (and you have uneven soil compaction,

If repotting was a huge hassle you might try another system. My biggest time constraint when potting up seedlings s having to write more tags because I split one starter pot into three and each starter pot is a differnt variety. Tearing little plants apart and cramming them into new pots is the quick and easy part.

Reason 4) Seed starting mix and up potting mix should be different for best results.

I would say also time is important! I plant trays of seeds maybe 200 seeds in one pack and it takes 10 minutes but to put in big pots it would take too long! another thing to consider is when they get about 6 to 8 inches high the weather seems to allow you to put them out in the open air in the bigger pots where its not so hot!!

I've not had a problem using a non-seedstarting mix for both stages. I used seed starting mix last year and the peatmoss wasn't ground up evenly so I spent a lot of time picking wads of it out. It also held more water than I prefer so ...never again.

I say there's nothing wrong with it if you have the space. and even more so depending on which seeds you are starting.

applestar wrote:Reason 4) Seed starting mix and up potting mix should be different for best results.

Not in my experience. I use Ferti-lome Ultimate for both and have for years.

Mike

OK let me rephrase/elaborate on that

If you are using really good quality potting soil -- what I consider premium -- yes, I have also experienced good results as far as germination. But I think extra fertility contributes to lanky initial growth.

For the most part though, cheap potting soil seems to be too heavy for seed starting in containers.

When I mix my own soil mix, I use less fertile mix for seed starting than for up potting.

Agree with all the reasons above. Also reason 4) [edit - oops, this should be reason 5, I lost count] a large pot of soil can hold too much moisture or be difficult to keep evenly moist. Baby seedlings are very sensitive to moisture issues. They can't be allowed to dry out or to stay too damp. By the time they are big enough to go in the 4" pot, they are a lot less vulnerable to either drying out or damping off/ too much moisture.

But yes, a lot of it for me is space issues. I germinate seeds on heat mats. I only have two of them (and don't want more, because then I would be using more electricity). So the seeds all have to be kind of crowded together on the heat mats. I plant them pretty thickly in the little cells.

applestar wrote:OK let me rephrase/elaborate on that

If you are using really good quality potting soil -- what I consider premium -- yes, I have also experienced good results as far as germination. But I think extra fertility contributes to lanky initial growth.

For the most part though, cheap potting soil seems to be too heavy for seed starting in containers.

When I mix my own soil mix, I use less fertile mix for seed starting than for up potting.

ugh. yes. I learned this from experience this year. decided to do things differently and killed nearly everything never again.