I'm planning to start some veggie plants indoors for the first time. The handful of books I've looked in all mention the step of moving the germinated seedling from a soiless mix in a heat-based environment to a potting soil mix in a light- based environment.
My question is, does anyone see a potential downside in filling a small pot with 80% potting soil on the bottom and 20% seed starter on top to eliminate the transplanting stage? The seed(ling) would still go through the heat then light stage, but not get transplanted.
Use soil. You'll often want to use a fine soil on top for small seeds, but I've never used soilless seed starter or sterilized soil for starting seeds. Mixing compost, garden soil and sharp sand makes a great seedling mix for me. Throw in some organic fertilizer such as rock dust, greensand or some other well balanced mix of goodies, and some coir for water retention if you like, and you'll have a great mix.
I think people generally start transplants in small containers and then transplant into larger containers because of space constraints. When I start my tomatoes, peppers, celery and parsley inside in early spring, I don't have much space so I start them in small blocks (I use soil blocks for transplants), and then I pot them into bigger blocks when it's warm enough for them to go into the greenhouse where there's more space. I start them all under lights, as the lights give off the heat that they need for sprouting. And many seeds need the light to sprout properly.
For cucumber and squash, and other seeds that are started later in the greenhouse, I start them in the blocks they'll stay in until they go into the garden. And it's worked fine for me!
I'm sure other's will have their own experiences to share. So take all the info you can, and work out what will work best for you in the space you have.
Good luck, and I hope your first seed starting adventure is a success!
My question is, does anyone see a potential downside in filling a small pot with 80% potting soil on the bottom and 20% seed starter on top to eliminate the transplanting stage?
The down side is if the pot is too small to keep the plant until time to set it out. If you have room for larger pots it is even better. I had some pumpkin seeds that sprouted in the pumpkin so I put them in 1/2 gallon pots in the greenhouse, it is too cool to put out true leaves but they are still growing roots. Past experience is that the larger the root ball the sooner thy start producing female flowers.
Seed starting in soil is fine and probably the best actually, what is needed most is soil to seed contact.
As far as size of starting container, I would use the largest for the length of time the new plant will have to stay in there.
I generally direct seed most of our veggies but for some we have to start them in the greenhouse, those seeds are put into 5 inch or 6 inch pots since we have the space for that.
I like to use as few steps as possible from sprout to placed in the growing space, it is less stressful to the plant and less work for me.
If you have no space constraints, go for your mixed approach. I never quite understood the fuss about soilless media for seed starting though. maybe it has to do with sterility and thus lower chances of seed rot? I use an organic potting mix and plug trays and have had no problems sofar.
One important thing is that most seeds need higher temps in germination stage than in seedling stage. Bottom heat is more efficient for this purpose... Lacking a heag mat or hot table setup I achieve this by placing the seed trays above my heat source (radiator). I also cover the trays with clear plastic so i dont have to water at all until emergence. After emergence you need proper light conditions straight away to avoid leggy seedlings and get good vigor. Seedlings benefit from liquid fertilizer feed especially in small containers. Watering with lukewarm water is a good idea as well.
Regarding size of pots: for tomatoes at least I actually prefer repotting / upsize potting multiple times. The reason is that tomatoes are very good at rooting from any section of stem that is buried. So when I transplant, I bury the plant up to its leaves. I often go further, trimming off most of the bottom leaves to provide more stem. I believe this practice results in a much larger, more developed root structure and a more compact upper plant.
The other practice I've found to be critical is setting an oscillating fan on the seedlings, from the moment they break through the soil. You can set the fan on a cheap timer, so it blows several times a day for a short period. Gradually increase the length of time and strength of the wind current. This will create stout, strong stems that can survive the harsh conditions outdoors .
I've used both soilless and soil mixes. Haven't noticed a difference.
Best regards - OD
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