Did I just accidently sterilize my soil and newly planted tomato seeds?


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I live in Durham, NC, and I've tried tomato plants a few different times with no luck! They always get very spindly and never produce much fruit (and what little they do produce is quickly eaten by deer).

Last year was my first real attempt. I strung fishing line around my planting areas and yard which seemed to keep the deer away! The plants grew, but they just didn't produce much fruit!

I think a big part of my problem is that I started from seeds way too late in the season, so this year I decided to start in January.

I invested in seedling heating pads. I planted my seeds in two five-gallon buckets and wrapped each with a heating pad, I then reused a small sheet of poly-insulation from my EveryPlate box to wrap around the outside of each pad/bucket. I had no idea that the seedling heating pad would produce as much heat as they did.! After two days I measured the temp and it was 108F!!!

I turned them off and I ordered a thermostat for the pads, but my question is did I just accidentally sterilize my soil and seeds? Fortunately, I just started with two buckets to get the hang of it, but the two seeds I started with was an "Early Girl" hybrid and a "July Hybrid". Would the Early Girl be more susceptible to the higher temp?

Should I just dump the buckets and start over, or would the two days not be enough to have killed things? At this point, I'm only out two days and $3 in seeds, so I don't want to wait a month, and then find out it was all for nothing if I should instead just remix the soil with fresh and replant the seeds.

Advice?

THANKS!
-Zac

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I live in Durham, NC, and I've tried tomato plants a few different times with no luck! They always get very spindly and never produce much fruit (and what little they do produce is quickly eaten by deer).

Last year was my first real attempt. I strung fishing line around my planting areas and yard which seemed to keep the deer away! The plants grew, but they just didn't produce much fruit!

I think a big part of my problem is that I started from seeds way too late in the season, so this year I decided to start in January.

I invested in seedling heating pads. I planted my seeds in two five-gallon buckets and wrapped each with a heating pad, I then reused a small sheet of poly-insulation from my EveryPlate box to wrap around the outside of each pad/bucket. I had no idea that the seedling heating pad would produce as much heat as they did.! After two days I measured the temp and it was 108F!!!

I turned them off and I ordered a thermostat for the pads, but my question is did I just accidentally sterilize my soil and seeds? Fortunately, I just started with two buckets to get the hang of it, but the two seeds I started with was an "Early Girl" hybrid and a "July Hybrid". Would the Early Girl be more susceptible to the higher temp?

Should I just dump the buckets and start over, or would the two days not be enough to have killed things? At this point, I'm only out two days and $3 in seeds, so I don't want to wait a month, and then find out it was all for nothing if I should instead just remix the soil with fresh and replant the seeds.

Advice?

THANKS!
-Zac

View attachment 74717
I think you are making things more difficult than they should be. Why are you planting your seeds (how many seeds) in a 5 gallon bucket? It is much easier to maintain moisture and temps in small containers. Planting seeds in a 5 gallon container usually means that what ever is planted in the bucket will stay there. It is much much easier to grow tomato seedlings and transplant them later into your 5 gallon bucket. I doubt if 108 degrees will do all that much damage as my garden soil reaches 120+ in the heat of the summer and my plants survive. The soil isn't sterilized as it takes about 160 degrees to accomplish this but it might have done something to your seeds. Tomatoes take about 6 weeks from seed planting to setting out transplants. I like to start my tomato seeds about 10 weeks before setting them out as I like large transplants. I sometimes have to repot my tomatoes 2 times before final transplant. Spindly leggy tomatoes are the result of not enough sunlight and for a good harvest proper fertilization throughout the growing season is a must. Fertilizing tomatoes begins when the plant has 2 sets of true leaves. Use a liquid fertilizer at 1/2 strength at every watering until 4 sets of true leaves. After 4 sets of leaves the plant is ready for final transplant and full strength fertilization. Fertilize every two weeks. Use only organic fertilizer. My date of last frost is about March 15 but I always wait until about April 1 to set out. I will start planting seeds this week and by April 1 they will be at least 1 foot tall and probably have buds starting to show.
 
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Thanks for the reply!

Sterilize was too strong a word, I meant more like euthanize. I didn't know if that temp might impact the seeds enough not to germinate, and/or mess up the soil biome?

I'm using the 5-gallon bucket because I am going to grow the tomatoes in these buckets. For my other plants, I am going to use a small seed starter tray and then transfer, but these tomatoes will grow in these buckets [I have four total, but started with two]. I used the seed starter for my tomatoes last year in March and they took ages to germinate and then stayed very small for another month! I'm thinking because my house is pretty cold (~68F), that may have been why they took so long to germinate? I think I also waiting two long before transplanting them from the seed starter to larger peat pots. I was waiting for them to beef up first, but once I transferred them to the peat pots they grew pretty quickly, but once I put them in the ground they grew spindly and didn't produce fruit. I think my main issue was not enough sun, as I was fertilizing with Miracle Grown every two weeks. I wasn't sure if maybe I was over fertilizing them (thus the spindly growth)?

THANKS AGAIN!
 
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I grew up in Alabama, where you put dirt in the plastic trays and planted a seed and tomatoes grew like the weeds they are, but in NC the soil is… different. Even when I supplement with bags of topsoil and mulch, the soil quickly becomes clumpy and stays wet. I don't know how to describe it better, as I've only had luck growing a small subset of things I used to grow in AL with no problem.
 
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Thanks for the reply!

Sterilize was too strong a word, I meant more like euthanize. I didn't know if that temp might impact the seeds enough not to germinate, and/or mess up the soil biome?

I'm using the 5-gallon bucket because I am going to grow the tomatoes in these buckets. For my other plants, I am going to use a small seed starter tray and then transfer, but these tomatoes will grow in these buckets [I have four total, but started with two]. I used the seed starter for my tomatoes last year in March and they took ages to germinate and then stayed very small for another month! I'm thinking because my house is pretty cold (~68F), that may have been why they took so long to germinate? I think I also waiting two long before transplanting them from the seed starter to larger peat pots. I was waiting for them to beef up first, but once I transferred them to the peat pots they grew pretty quickly, but once I put them in the ground they grew spindly and didn't produce fruit. I think my main issue was not enough sun, as I was fertilizing with Miracle Grown every two weeks. I wasn't sure if maybe I was over fertilizing them (thus the spindly growth)?

THANKS AGAIN!
Yes, it was your soil temp that caused slow germination and growth. I keep my seed starting potting soil as close to 80F as I can and germination is usually 5-8 days. Even moisture is also very important. Even good sized tomato plants require warm soil to grow rapidly
 
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I grew up in Alabama, where you put dirt in the plastic trays and planted a seed and tomatoes grew like the weeds they are, but in NC the soil is… different. Even when I supplement with bags of topsoil and mulch, the soil quickly becomes clumpy and stays wet. I don't know how to describe it better, as I've only had luck growing a small subset of things I used to grow in AL with no problem.
First of all NEVER plant seeds in topsoil. Garden soil mixed with 25%-30% compost is OK but for best results in seed starting potting mix is the best. It sounds as if you have heavy clay soil. It takes time to amend clay. Adding sawdust, compost, manures etc are what is needed but not in amounts of over 30%.
 
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First of all NEVER plant seeds in topsoil.
Sorry, that wasn't clear. I meant adding topsoil and compost to my actual garden soil (because it's very high clay content). Even doing that yearly, the resulting soil just seems very anaerobic.

I usually plant my seedlings in the Jiffy peat pellets, but for my five gallon buckets, I put lava rock in the bottom, then mixed topsoil with 25% compost, but then I put about a 1.5" inch of the Jiffy seed-starter brick soil (made from coconut mulch) on top of that to plant the seeds in. I left about four inches at the top so that once they reach a certain size I can put more soil around them.

My thermostat arrived today, so I'm going to set it at 80F, and see how it goes!

Thanks again!
 
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Sorry, that wasn't clear. I meant adding topsoil and compost to my actual garden soil (because it's very high clay content). Even doing that yearly, the resulting soil just seems very anaerobic.

I usually plant my seedlings in the Jiffy peat pellets, but for my five gallon buckets, I put lava rock in the bottom, then mixed topsoil with 25% compost, but then I put about a 1.5" inch of the Jiffy seed-starter brick soil (made from coconut mulch) on top of that to plant the seeds in. I left about four inches at the top so that once they reach a certain size I can put more soil around them.

My thermostat arrived today, so I'm going to set it at 80F, and see how it goes!

Thanks again!
Thermostat keeping everything at a perfect 80F! :nailbiting:
Do you have a soil thermometer? You can't rely on a thermostat to keep soil at the correct temp. It keeps the mat at 80 but not the soil. Soil absorbs heat.
 
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The thermostat that I have has a sensor that you put down into the soil, but only one sensor for all six mats, so I've been measuring the others with a separate thermometer to make sure they are all synchronized. So far, so good!
THANKS!
 
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Woot, guess I didn't kill off anything! They are sprouting like crazy!
 
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100% too complicated.

99 times out of 100, tomato seeds will germinate the other 1 time is due to other issues than the growing medium itself, because the seeds are independent of the soil, containing the.
The temperature for germination is wide, so the usual advice is just a pot on the windowsill, covered with poly(ethyilene)thene to keep humidity high.
The good news is that you appear to have heavy clay soil, which, although slow to warm up, retains nutrients & will halve your watering requirements.
For planting outdoors, the rule of thumb (IN THE UK) is to sow your seeds 6-8 weeks prior to your expected last frost. (Perhaps our N. American friends can advise if that is good in your area. )
Planting too early is usually the cause of lanky plants, as it results in too much heat and too little light.
Tomatoes grow best at 15C with at least 6 hrs of sunshine a day.
It's easy to molly-coddle tomatoes, but their hardy little buggers who really, really, really want to grow.

Now, perhaps we can look at the other stages of growth (vegetative & fruiting) and see if there are any ways we can help there.
In order to do so, I'll need to know a little more about your climate and your methods.
 
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I can only judge based on my own experience. Last year I tried the "just plant the seeds in a container on the windowsill" method and had very poor germination and even worse maturation. This year I decided to start much earlier, using the buckets, heating pads, and cheap grow lamps, and so far my germination rate is great, and after only a few weeks I'm already thinning the seedlings in the buckets (replanting the one I pull into their own little peat pots to grow separately). So far both the main buckets and the new peat pots are growing at a much more constant rate. I'm also seeing a much faster germination rate with my peppers. I've also tried growing foxgloves from seeds several times with no success, but this year, using the heat pads I've seen a near 100% germination rate! I just transferred the small peat pellet germinated seedlings to larger peat pots, so I'll let folks know how those go.

So I am quickly becoming a huge fan of the heat-pad/grow-light-based approach, and would highly recommend it for others that have had poor results with "windowsill container" seedling growth.
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The overwhelming likelihood is that how the seeds were taken & stored (probably before you bought them) was the problem last year.
 
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"I think my main issue was not enough sun, as I was fertilizing with Miracle Grown every two weeks. I wasn't sure if maybe I was over fertilizing them (thus the spindly growth)? "
Pretty sure that would be lack of light, that doesn't sound like too much fertiliser to me, but it sounds expensive. The cheap tomato fertilisers are usually just as good, I don't know how they label things over there, in England you usually get two sets of figures, one for Ireland one for the UK. UK figures show total amounts of things like nitrogen and potassium, Irish ones available amounts, but either way you should be able to hold the packs next to each other and compare, my experience is that you are paying more for the brand name rather than for quality. Tomato fertiliser is actually very well balanced, and suitable for almost anything that needs help.
 
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...but it sounds expensive.
Here, around December/January, you can buy a large container (10lb) of (general) Miracle Grow for the same "per unit" (gram/lb/etc) price as the cheaper brands come summer, and the stuff lasts forever.
 
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