Dean A
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Growing organic tomatoes from seeds

Hello everyone!

I find it really hard to grow tomatoes from seeds organically because they are such heavy feeders. I find that the leaves start turning yellow on the new plants before transplanting outside. So then I need to feed them miracle grow 18-18-20(which I don't want to) and then they start thriving again. When ready to transplant outside I mix my existing garden soil with compost and manure along with an organic fertilizer 3-9-7. What am I doing wrong???? Help please! Is growing organic tomatoes a myth?

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If you want to grow organic tomatoes, try starting them outside in the ground instead of indoors as soon as you can. It is very hard to grow anything organically in pots. Organic fertilizer is not readily available to plants and not in the quantity they need. Organic fertilzers need to be converted into inorganic forms to be able to be useful to plants. Unless you have a large soil volume and have sufficient numbers of microbes it is hard. You will need to constantly be feeding the seedlings which defeats the purpose of being organic in the first place.

I have problems with alkaline compost as most plants like a slightly acidic environment and the compost holds too much water and I end up with seedlings dampening off. I can only add a couple of handfull of vermicast to my potting mix without causing problems. Other people said they don't have a problem but they probably use a different mix and don't water the same way I do.

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I use vermicast, too. I mixed vermicast with baby worms and worm cocoons in it with my tomato and pepper seed starting mix. So far, every group-sown cup with at least one biggest seedling growing true leaves had one or more baby worm in it, and the baby worm was curled in the roots of the biggest seedling. In some cases, "vermed" seedlings had jumped ahead of "un-vermed" earlier sprouted seedlings.

I add more (and bigger worms) to the uppotting mix as well as UCG's (used coffee grounds). Greensand, rock phosphate, dolomitic lime.

My vermicomposting bins are not that big so I try to maximize and put the extra worms to work in situ :wink:

While the seedlings are inside, I water with UCG and used tealeaves steeped water, rinse water from finished beverage containers (milk, juice, soda, etc.), rice and beans rinsing water, soaking water. Vermicast tea. Diluted AACT (actively aerated compost tea) from vermicast.

I do use organic fertilizers when I have them or when I don't feel like mixing up stuff on my own but they usually smell bad so only very small amounts if added to soil mix. I also put small amounts in their water once they go outside to be hardened off. Also add compost from outside compost piles to the water, but usually don't get large quantities of AACT brewing until after temps get warm -- after first frost.

...maybe you should tell us exactly how you are growing your seedlings. It's hard to advise without knowing the details and what I do out of habit might not be obvious and not fully explained.

Greener Thumb
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Hi Dean A,
Tomato plants thrive so well in composted cow and chicken (mushroom) manure! I wouldn't suggest that you add it to seedling while they are little and inside.
Try to plant the seedlings outdoors as soon as possible, and add some composted manure.
Last year I experimented with growing my tomatoes in 1/2 garden soil, 1/4 mushroom manure, and 1/4 cow manure mix! They grew like crazy!

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So you say they're turning yellow before transplanting outside, but you don't mention what potting mix you're growing the seedlings in, or if you've even fertilized them organically in their pots.

I grow awesome organic tomatoes from seed every year. I start them in single cells, transplant them to larger pots after a few weeks, and then once more into gallon pots before they eventually make it into the ground. I add appropriate amounts of fertilizer to the soil at each transplant, and they do great.

If you are fertilizing your potting soil, are you leaving them in the original pots and letting them get root bound? If you're fertilizing, giving them larger pots progressively, etc, and you're still having problems, I'd suggest adding a small amount of garden soil to your potting mix to start some microbes digesting the stuff in the soil.

But I'd be curious to hear a) what your potting mix is, b) if you're adding organic fertilizer to the potting soil, and c) if you're repotting the plants appropriately.

Mark O
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Hi Fellow Gardeners!!!

I have had a hard time growing organic tomatoes from seeds! I use potting soil and they start germinating.Everything is going well so far. When they get two true leaves, I feed them liquid organic fertilizer 3-4-3. I keep doing this every 2 weeks applying the fertilizer. After 4 to 5 leaves form, the leaves start turning yellow and the small plants don't look healthy. What am I doing wrong??/ Please help! Am I using the right soil and fertilizer? And so I break down and give them miracle grow 20-24-18 and they look great again but I want to go all organic.

Greener Thumb
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One question: do you re-pot at the two true leaf stage? After transplanting I don't generally fertilize more than once or twice until planting in the garden.

Another question: do you have drain holes in the bottom of the containers? You may be drowning your seedlings and this would cause a yellowing of leaves and an unhealthy look.

One last question: What is your light set up. Florescent lights will not burn the leaves but incandescent bulbs will get hot and the yellowing may be sunburn. If these plants are outside they may get sunburn or windburn.

Make sure your posting soil is soilless mix not garden soil. Once I used soilless mix with the moisture retainer (or whatever it is called) and had terrible luck. I would cut back on the fertilization and make sure the soil dries out between watering.

Let us know where your are and a little more about your growing process,

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Location: Portland, OR

I've seen a couple people post about this recently. What I've noticed is it seems (the other poster hasn't returned to answer questions about what they're using, so I'm guessing somewhat) that people are conditioned to think of fertilizer as something extra that you "feed" to the plants, usually in a liquid medium like you are now. Combined with potting soil, which is not very nutritious for plants of any size at all, typically, and the tomatoes end up terribly malnourished.

I would encourage you to think, instead, of fertilizer as something you add to soil to improve a plant's ability to grow in that soil.

When growing any plants, but especially a plant indoors and organically, your job is to think like the plant. What does a plant need to thrive (not just survive)? You have to provide it. Light and water in appropriate quantities, temp, and soil that is adequately nutritious are the main ones, obviously. Miss on any of these and your plants will not be healthy. If your soil/potting mix/whatever you want to call it is so sterile and nutrient-poor that you have to supplement any liquid fertilizer (whether it is organic or MiracleGro), you haven't created a good soil for your plant to grow in.

So... here's the fertilizer and potting soil I use when growing plants indoors. This is also the fertilizer I add to my vegetable beds. No reason for them to be different - again, I want my indoor-grown tomato seedling to grow in conditions that let it thrive. Those conditions are the same indoors and outdoors - the plant doesn't suddenly need different things to thrive once you put it outside.

First let's mix our fertilizer... the ingredients (fertilizer mix, agricultural (not dolomite!) lime, and gypsum
Note what this fertilizer is made of. This is what's called seedmeal-based fertilizer. If you've never grown veggies with seedmeal, you will be pleasantly surprised. It is a powerful, natural, slow-release organic nitrogen source. This means you can't really over-fertilize, and your plants are fed naturally over a long period of time, instead of given a blast of nitrogen (liquid fertilizer) and then left to starve until the next scheduled "feeding."
Add approximately a gallon of the fertilizer to a bucket, and add one pint lime, one pint gypsum, and mix thoroughly. Leaving you with awesome organic fertilizer for any soil (indoors or out) you want:
Organic potting mix:
The angle on the camera is weird, but this is about 1/2 of a 5 gallon bucket of potting mix, and a slightly heaping spade-ful of fertilizer.
Add the fertilizer to the potting mix, mix thoroughly, and you have powerfully nutritious potting soil that will feed your tomatoes for as long as they are not root-bound in your pots (always transplant to larger pots before they get too root-bound, and use the same fertilized mix when you do - thus adding more fertilizer to your growing plants!).

Here are this year's tomato seedlings 6 days ago when I transplanted to larger pots:
Here's what they look like today:
Nutritious soil = happy tomatoes!

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Most commercial potting soil already has Miracle Gro or something similar in it. If you are using that and then adding full strength fertilizer every two weeks, you are WAY over fertilizing and probably burning your plants.

When I plant seedling in Miracle Gro potting soil, they don't get ANY other fertilizer. They get fresh potting soil (with fresh M-G) when they are up-potted. So that is all they need.

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Super Green Thumb
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Location: TN. 50 years of gardening experience.

I think anything we grow in our garden is organic. I have found that all potting soils are not the same some have no food value at all for plants. I have also found that composted manure is not always good either the last 2 bags I bought looked like 90% saw dust mixed with just enough manure to turn the saw dust black color. It is not easy to duplicate mother nature growing tomatoes inside the house. I have very good luck planting about 10 seeds together in the garden most will come up the plant that takes over is the 1 that stays all the other plants get pulled up. When planting in the garden I dig a 10" flower pot size hole for each tomato plant then dump in about 1/4 cup of 15/15/15 fertilizer. Cover the fertilizer with about 2" of soil then plant the tomatoes. If you buy plants plant them deep the stem will grow roots anywhere soil touches it. I don't grow seeds inside the house anymore I plant directly in the garden or I buy plants. Plants in a 6 pack are only $1.49 seems silly to plant seeds I only need $4.50 worth of plants. No matter where plants come from they will be organic once they are planted in MY garden. I don't do compost but this year I had so many tree leaves I had to rake them to the corner of the yard to keep them from killing the grass. I have 4 large 30 gallon black plastic trash cans I guess I will pack trash cans with leaves and 5 cups of wood ash and 1 cup of UREA fertilizer then leave them in full sun in 30 days in 95 degree water it will be finished compost. If those leaves were not in the shade they would dry out and I could burn them, ash is excellent fertilizer.

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