Best Way to Start Tomato Seeds Indoors (or Outdoors)

Two years ago I put out a complete growing guide for tomatoes and it is still the number one video on YouTube for growing tomatoes. It's almost got six million views at this point. I can't believe it. Since then I've harvested over 800 tomatoes from a 40 square foot raised bed. And those weren't cherry tomatoes. Those were big juicy heirlooms and paste tomatoes. The success of your tomatoes ultimately goes right back to the day you sowed the seeds. So today I'm going to walk you through exactly what I do step by step to get the strongest tomatoes to plant out into the garden in just a few weeks. Hey, I'm Brian with Next Level Gardening and if you're looking to join an online garden community that offers tips, tricks, and support to help you get your garden to the next level, you're in the right place. Start now by clicking subscribe and hit the bell so you never miss anything. Now let's get growing. So tomato seeds can be started indoors six to eight weeks before your last frost date. They can be planted in the garden, direct sown, or transplants about two weeks, two to three weeks after your last frost date. So before we get started with the process, I'm going to go through the varieties that I'm going to be growing this year and let me know down in the comments what your favorite tomato variety is or and or which tomato variety you are looking forward to growing this year the most. So I've never really grown a lot of cherry tomatoes, mainly because they take up a lot of space that I just don't really have. But this year I am making space for two. The first one is Sungold, which is supposed to be the sweetest tomato you can grow. So I'm looking forward to trying that and I love my yellow tomatoes anyway. And the second one is Sweetheart Cherry. This one's from Baker Creek and I think it's new this year, but it's supposed to have a sweet, almost berry-like flavor, which sounds great. And it's shaped like a heart, so how can you not love it? I feel like a newscaster sitting here at this desk. Anyway, in addition to those, I'm going to be growing my absolute favorite. If you've been around any time at all, you know my absolute favorite tomato is Kellogg's Breakfast. It is a super sweet, super firm, yellow heirloom tomato. I grow it every year. I think this is the fourth year I've grown it and I don't think I'll ever not grow it. And then the other one is going to be one that I started, I think it was the first year I grew it last year. It's a red one, which is rare in my garden, but it is from Burpee and it's a steakhouse. It's called Steakhouse Hybrid and it is a beefsteak tomato. But it's super, it's one of the biggest tomatoes you can grow and the flavor was out of this world. Now, last year was the year of the San Marzano. Before that, I had always grown Roma tomatoes for canning and for paste and freezing and that kind of thing and sauces. And then last year was San Marzano's, which they did okay. You know, they weren't like the best tomato ever. They produced a lot, but it was over a very long period of time. In fact, I've still got them growing from last year out in the front yard, which have to be removed so we can get started on our edible landscape series. I think that's starting next week. So I have to get those, get those gone. But the San Marzano's, they were fine. But this year, I am trying the Amish paste tomato, which is supposed to be like the best type of paste tomato you can grow. So I'm looking forward to that. So first I'm going to talk about what I'm going to sow the seeds in container wise. And that is going to be in a red solo cup that is repurposed. I've been using these same cups for several years and they will probably go many, many more years before I have to get rid of them. You can use any color of a solo cup. It doesn't matter. The only thing you need to do with the solo cups is to put a hole or a few holes in the bottom. This can be done with a drill. You can drill through several cups at once. I had a viewer say that they used a soldering iron, which should probably do really well, might create some funky fumes, but do it outside. I really love the solo cup because they're a perfect size. I'm not going to plant my tomatoes out in the garden for another six weeks, at least because right now my tomato bed is full of peas and they aren't even producing yet. So they're going to be there a little while longer and you can use whatever you want to use. Just make sure that the container is taller rather than wide. And the reason is that because tomatoes are one of the few plants that you can grow that actually grow roots on their stem, wherever they touch the soil and the more roots that you can get the plant to develop and the sooner that you can get them to develop those roots, the stronger and more vigorous the plant is going to be when you finally put it out into the garden. A more robust plant is going to produce more fruit and is going to have a better ability to fight off pests and disease throughout the season. And this method works for both determinant and indeterminate varieties of tomatoes. Now, if you don't know the difference between the two, I'll give you a real quick crash course on it. A determinate tomato, like a Roma, grows to a specific size, puts on all of its fruit, and that's it. It's done. An indeterminate tomato will grow and grow and grow as long as there's weather that doesn't kill it. So as soon as the frost comes, it will kill the indeterminate tomato. But in the meantime, it's produced fruit the entire time it's been growing and it can grow 10, 15, 20 feet or more depending on the length of your growing season. So again, this method works for both of those. So you don't even have to worry about the difference right now. Now, as far as the growing medium that we're going to be actually sowing the seeds in, I am going to be using a mixture of 50% coco coir and 50% peat. And then I'm going to throw in a couple handfuls of perlite. Now, I just like to mix it up all at once and the measurements do not have to be exact. See what I mean? Just mix it all up. And the perlite is just going to add a little bit of drainage and lighten up the mix a little bit. You can also just use indoor potting soil or potting mix. It is sterile and so your seedlings aren't going to have, they're going to have a better start with less disease issues. You also want to always make sure that your planting mix is pre-moistened. It should have the feeling of like a wrung out sponge. All right, so when it comes to filling the cups, we're only going to fill the cups about halfway, maybe even a little less. Just like that. Now, that is very important going forward. Halfway max. So we're going to put two seeds in the soil and just push them down about a quarter to an eighth of an inch and cover them up. The extra seed is just an insurance policy. So in case one doesn't germinate, you've still got a plant for each cup. Now, if both of them germinate, you want to wait until they both have their first set of true leaves. The first two leaves that come out of the soil are the seed leaves. And then the second pair of leaves, which look like actual tomato leaves, those are the first true leaves. Once they've got that, choose the weakest one and snip off the stem. Or if you're not heartless, you can go ahead and pull the entire thing out and tease the two apart and then give them their own separate cups. Now, once they have their first set of true leaves, you can begin to fertilize them. Every two weeks, you're going to want to mix up a liquid organic fertilizer, half strength. I use Neptune's Harvest Fish and Seaweed Formula. And any products I mentioned in this video or always, they are a link below a page on my website. It's called Products I Love and you can find all the products I love there. Neptune's Harvest has a link on there that actually will give you a discount. So if you want to head over there, click the link below. And by the way, if you're getting something out of this video, please click the thumbs up button. It really helps out the video, pushes it out to a wider audience. If you want to share it, that would be great. I would be personally appreciative. The best way to water seedlings is from the bottom. And so you want some kind of a tray that doesn't have holes that you can put all of your solo cups in and then fill the tray maybe half full with water. Let the cups and the soil soak up the water. And then once they've done that, remove the cups, dump the water. You don't want your seedlings sitting in water. And then put them back. Now, a humidity dome will help keep the moisture in while the plants are germinating. And this humidity dome, I have this on my website as well. It came with the tray, so it's all in one. Now, once the seeds have germinated, you want to remove the humidity dome. You're not going to use it anymore. If you really want to supercharge germination and almost cut the time in half, then you can get a seed heat mat. And that just keeps the ambient temperature below the tray at about 70 or so degrees. And it's going to, I think my tomatoes that I've got right now growing in the garage, they germinated in about four days. Same with the humidity dome. Once you have germination, you want to turn the heat off. Now, if you have any more questions about starting seeds in general, I did a video last week that I will link below. In that video, I talk about grow lights and you will need one if starting seeds indoors. A lot of people ask if you can grow them in a sunny window. Probably not. If your window receives six hours minimum of direct sunlight, not just it's bright, it needs direct sun six hours a day, then maybe. All right, now we're jumping ahead. And when your tomato plants are growing and they've reached the top of the cup or a little further, this is where we're going to turn a regular tomato seedling into a supercharged tomato seedling. So what you want to do now, this is optional, but you can remove the leaves that are below the rim of the cup. And all we're going to do now is take some more potting soil and fill the cup the rest of the way up to within about maybe a half inch, three quarters of an inch of the top of the cup. If you've ever hilled up potatoes, same idea. Now, all along that stem that we just buried, more roots are going to develop. So in just a couple more weeks, when we are ready to plant this in the garden, this entire cup is going to be full of roots that come off of the main trunk. That is going to create a super strong, robust plant to go out into the garden. Now, when these are ready to go out in the garden, I'm going to have another video because at that time, there's a whole other thing you can do to make some more magic happen. But for now, we're done with that. And I'm going to continue sowing my tomato seeds here. And while I do that, if you stick around, I've actually chosen some questions from last year's sowing tomato seeds video that you guys had that I will now answer because I think they're just as pertinent this year as they were last year. Okay, so the first question is, great information and thanks for your videos. Quick question, should the seeds be soaked overnight before sowing them into the cups? Some people advise that this is a good step for germination. Just curious if you've tried this. Thanks again. For some seeds, that is a good thing to do, and it does help. For tomatoes, I don't think it's at all necessary to take that next step, that extra step, especially if you're using a heat mat. There's just no need. So I would say no. I want to save you extra steps. And if you don't have to do something, I'm going to let you know. But good question because, yeah, people do recommend that for lots of different types of seeds. All right, the next question is, can I start the seeds in the pot I intend to grow the plants in? I don't have room for a bunch of cups. I just want to plant the seeds where they are going to be grown. Well, as far as enough room, it takes more room for big pots. So it depends on how many you're growing. I suppose if you're starting them outside, yeah, go ahead and do that. If you are in a spot right now, I'm not putting mine under the grow lights. We are at a time here where we have passed our frost date. We're actually three weeks past our frost date. And so, yeah, they're not going to go inside. They're going to be starting outside. So for space saving, yeah, you can do that. Yes, if you are in a spot to do that, you don't have to start them indoors. You don't have to start them in cups. However, if you are growing them in a pot, I would still plant them low, just like this, and then fill the pot as the tomato grows. If you're planting them in the ground, then you could hollow out maybe a six inch depression in the soil, plant your seeds in that, and then fill that depression back up as the plants grow. That would be my advice. That way you still get to take advantage of, you know, the extra roots. I choose to start my tomatoes in cups, even if I was able to transplant out right now, because the taller that tomato grows, so by the time this is, you know, five weeks from now, it's going to be like this tall. At that point, I'm giving you a sneak preview here, all that stem that's been grown since then is all going to be buried under the ground to grow more roots. So if you're just planting right in the ground, you're not going to get that extra benefit of all of the extra roots. The next question is, you said to plant the seeds in a solo cup, but solo cups come in different sizes, eight ounce, 16 ounce, and 20 ounce. Can you tell us the size you use and recommend? I didn't know they came in sizes. Does it say on here? I would guess that's eight ounces, right? I don't know. Whatever this size is, it's about that compared to my head. I don't know. I suppose if you had a longer time where they had to grow indoors, then bigger would be better. But for most situations, I think this is just fine. The next question is, would I still need a grow light if I have a south facing greenhouse? I do have a heat mat. The greenhouse on a sunny day gets to 94 degrees. I have to open the doors. If you have a greenhouse, that's totally fine. Another thing I didn't mention with the other question about starting them in a pot outdoors or in the ground outdoors, is you want to make sure that your temperatures, nighttime temperatures, are consistently in the 50s and not below. So if they're in the 50s, if your greenhouse keeps them in the 50s, that's perfect. So I'm going to continue sowing these seeds. There's nothing new that I have to teach. So I hope that you got a lot out of this video. Again, if you did, thumbs up, comment, like, subscribe, all that good stuff. But I hope that you're ready to have your best tomato year ever, because that is what's going to happen. Have a great rest of your weekend, and I'll see you guys on Tuesday.