Here is a new thread for reporting how your 2026 grow out of our promiscuous tomatoes are doing. We have three tomato offerings in 2026.
Profoundly Promiscuous an offering of Joseph Lofthouse’s breeding descendants from his breeding with Solanum habrochaites and Solanum penellii. This category should have mixed breeding systems. Some plants should be self-compatible but a few amongst them are likely to be self-incompatible. This is also the category that some of the other named selections Joseph has released over the years belong in- those with the wild ancestors. If in doubt about that ask- as we also worked with some roughly 100% domestic ancestors in the past- and we are moving away from those.
Obligate Outcrossing an offering of Joseph’s breeding selected carefully for self-incompatible traits from the two wild ancestors. This is the culmination of many years of careful breeding for promiscuity- and needs to be carefully stewarded by you to maintain its important traits!
Solanum penellii one of the wild ancestors that enabled the self-incompatibility. A hard green wild tomato with beautiful flowers and unpalatable fruits that only a botanist could love!
As you grow these tomatoes. Make or simply allow crosses with them. Allow them to adapt to your individual gardens and save seed for the 2027 seed share this would be a great place to post about your journey.
In 2025 for me the Obligate Outcrossing strain was most carefully rouged for the important traits like stigmas that stick out quite a lot and signs that they are not Self Compatible- like they got pulled if they produced fruits immediately on first flowers before bumblebees came into the picture. I also had best success with them in the direct seeded row.
It seems possible to me that in 2026 as my family works on downsizing that I may not be able to start many tomatoes from transplant. I’ll have to carefully prioritize some F1 hybrids I made in 2025 and some wild ancestor tomatoes to grow out to make new crosses with. One of which is a cross between a tasty strain of the Profoundly Promiscuous tomatoes and a South American indigenous domesticate with stigma’s that stick out quite a bit called LA0410. That very likely means I’ll be direct seeding the GTS mixes again this year. I’ll likely do that in three parallel rows. One row for Profoundly Promiscuous, a center row for Obligate Outcrossing, and a third row for some of my crosses with Joseph’s Profoundly Promiscuous strains. A single such plant survived parallel to the Obligate Outcrossing tomatoes last year- and I hope to replant all of its offspring this year- probably as well as some other relatives. It resulted when I crossed Joseph’s promiscuous tomatoes with a strain of Solanum habrochaites called LA2329 and then backcrossed to a cross of Joseph’s domestic line Big Hill with my own domestic line Mission Mountain Sunrise. I’m curious to possibly learn if it crossed with the Obligate Outcrossing last year and what that might look like.
Last year I picked up a few more crossing tips from the standard crossing advice available here: Guidelines for Emasculating and Pollinating Tomato Flowers | TGRC. Specifically, If you are having difficulty collecting pollen which I was from our promiscuous lines- you can detach some flowers, split the anther cones open and let them dry a little while to release the pollen. I expect that doing so will allow me to make crosses more easily with our Profoundly Promiscuous and Obligate Outcrossing tomatoes again in 2026. I don’t think you’ll have any difficulty getting pollen from Solanum penellii though if you can get it to flower- a pollen vibration tool should get an abundant amount of pollen to release from that!!! I hope to make more crosses this year between the Obligate Outcrossing and wild tomato relatives I’ve been working through some accessions of current tomatoes Solanum pimpinillifolium for a few years- and it’s an ongoing labor. I’d like to use the palatability of the current tomatoes to create or add to the diversity of an Obligate Outcrossing strain that is greater than 50% wild genetics!
I don’t plan to grow Solanum penellii myself this year due to the downsizing. Though I really wish I could! I think of it as a tomato that only a botanist can love and so if you grow it this year, I hereby dub thee a fellow botanist. In my experience it and Solanum habrochaites should be started extra early. However, Solanum penellii and Solanum habrochaites are an extremely deep source of heterozygosity and thus genetic level variation and without variation true adaptation cannot happen in a plant population! The flip side is that we’ve had to dilute those genetics quite a bit in the past to return to palatability.
With my limited seed starting space, I’ll start the transplants just six weeks or less from average last frost. I’ll direct seed 20 days before average last frost.
Joseph’s direct seeded tomato line is a subset of the Profoundly Promiscuous or Lofthouse promiscuous project. A great selection which should have a good chance of growing seed to seed direct seeded for lots of folks. Though in many gardens a lot of tomatoes should work direct seeded. Joseph’s conditions took a lot of adaptation to get there. I thought it would be far harder for me than it was- but in 2017 the first year I tried it, most tomatoes worked direct seeded and I’ve been using it for part of my crop every year since. This year I may lean heavily on direct seeding.
I’ve done two seasons of direct sowing some tomatoes so far.
My layman hypotheses:
Direct sowing tomatoes allows an amateur gardener/breeder to sow thousands of seeds rather than hundreds. Perhaps this has advantages in terms of selection. Or perhaps we just cull a bunch of seedlings that weren’t as lucky as the selected ones.
Direct sowing may introduce a strong selection pressure which will be quite useful for people who have short seasons. Eventually, I will mostly be growing tomatoes that have had years of direct sowing on my land. Should be advantageous, whether I start them early indoors or direct sow them.
I think that the ability to be direct sown itself is highly conserved in tomatoes. Most varieties can be grown that way as long as they are short season enough for my climate. I do think it helps to right size the growing season of the tomato to the place its grown. I also think that it does allow the breeder to sow many more seeds of an F2 and select amongst those plants those that are right for the climate. There do seem to be limits though. I direct seeded a 50% Solanum habrochaites F2 a few years ago and it failed to set seed in the time it had. It was very interesting though!
We are going to try starting tomato seeds this year.
Last year was a failure due to inadequate lighting in the seed starting room, then setting them out too early as transplants.
This year we are growing: Promiscuous, Obligate Outcrossing, Q-series Panamorous, Wildling Panamorous, with two open-pollinated types, Genuwine x Beefsteak, and some amazing large roma tomato from Walmart.
As for the Genuwine x Beefsteak selection: we don’t know if these actually crossed with one another, but they were the only two tomato plants, and were planted one next to another, fingers crossed. It produced lots of large delicious red fruit with minimal steaking, little watering/fertilizer and intense 10A heat/humidity/droughty conditions.
Tomato seeds were started on 2/16/26, and are looking nice.
Here is what I would do with those selections. I would take Promiscuous, Q-series Panamorous, and Wildling Panamorous and grow them together in the same row as these all belong with our profoundly promiscuous offering. I would grow Obligate Outcrossing in a parallel row. I would rogue both rows for any plants that don’t have correct promiscuous type flowers. I would also rogue out any plants that set super early fruits before bumblebees are active on the plants. If any closed flowered plants survived all this careful rogueing I would endeavor to not save seed from the closed flowered plants- but plenty of seed from the open flowered plants. Then I would keep collected seed from both rows separately and return the extra of it to going to seed carefully labeled as either Profoundly Promiscuous or Obligate Outcrossing. It would go into next year’s tomato mixes: obligate outcrossing and profoundly promiscuous.
With Genuwine x beefsteak and the Roma. I would grow them separately from the others by say perhaps 10 or 20 feet - whatever is necessary in your climate so the vines don’t get mixed with the promiscuous project. Then I would watch some of the tutorials on tomato crossing on YouTube. I’d get a black plastic spoon or save one from a sundae at Costco and a pollinator tool off Amazon. I’d also get a nice set of forceps. I’d emasculate flowers on both of these and pollinate them with pollen from the obligate outcrossing plants. You might have to split and dry anthers to get the pollen. I would save the seed from those hand crosses for my own use the next year. Then next year in 2027 I’d grow the parents again for comparison to make sure the crosses worked as well as the F1 seed I had produced. Once I confirmed beyond any doubt that the F1 plants from my own crosses were in fact new crosses with promiscuous project ancestry I would save a great deal of seed from them (The F2) and share it back to the group for the profoundly promiscuous mix. That F2 generation is likely to be somewhat magical.
Thank you, for your reply, and sorry for my late reply.
I will conduct this year’s tomato project the way that you described, and will be sure to document it’s progress.
One last question, how long should I wait until I transplant all of the tomato starts outside? I heard to transplant them outside when they have three set of true leaves?
Transplanting tomato starts outside is tricky. More foliage is helpful in case some burns off due to sun or frost or both. Typically, people transplant six- to eight-week-old transplants. Though much depends on how you grow your transplants. Leggy low light level transplants should typically be buried deeper either horizontally or vertically so that the leggy stems are covered. Transplants grown at higher light levels should be sturdier and don’t need as much burying- though some burying can be a good backup in case the above ground portion burns or freezes off. I recommend doing some direct seeding as a backup to the transplanting and vice versa.
I started the Profoundly Promiscuous seeds in a tray last week. I also started a tray with wild varieties (pimpinellifolium, Cuatomate, and an unknown), and a mix of 30 heirloom varieties and a couple grexes.
Ultimately, I’d like to steer towards direct seeding but I thought it would be best to do that selection after I have collected from the survivors this year, as I’m also selecting for drought tolerance and early fruit set.
My growing season is long (220 days or so frost-free) but fairly cool and often cloudy/rainy in shoulders and smoky in the summer. I often get volunteers but they aren’t usually able to fully mature fruit. The site grows black nightshade like crazy so I’m hoping the conditions will be right for tomatoes with the right genetics.
My plan is to allow all the PP seeds to grow in the cells under lights (no thinning) and set them out in clumps early (perhaps when nights are above 40f). I’ll also direct seed my extra mixed seeds nearby (all varieties, divided into rough slicing and cherry streams) once the soil is hitting 60f.
Is this a sound plan? Is there anything I should adjust or consider?
Should I keep some separation or just jumble them all together? I have plenty of space and I’m not worried about fruit yield, just strong genetics for subsequent years.
It is an ok plan! It really depends on what you want. Tomatoes are fairly plastic. I grow lots of small tomato plants badly. Not a few tomato plants well. One thought. Why wait for 60 degree soil? I direct seed about 20 days before expected last frost which is May 15th. So say roughly April 25th. If the soil is cold the seeds will wait to germinate. If its warm the seedlings will grow about an inch high- and the few times that has happened enough of them have survived that last frost.
If you want to return the Profoundly Promiscuous tomato seeds to the seed share keep them physically separate from the others but close enough for bumblebees to transfer pollen.
Mixing vs. separating your other tomato varieties is up to you. I keep mine separate because I like to know as best I can what the parents of my own breeding lines are.
Thank you for the input. I was just afraid of the seeds rotting in the cold wet. I can certainly sow them earlier. And I will keep the Profoundly Promiscuous seeds separate.
One caveat, if you normally plant later to avoid seeds rotting in the cold wet- keep doing that! I’m used to my own climate and place. I haven’t had tomato seeds rot yet that I planted, but here enough water to get the seeds to germinate is a little uncertain. A one-inch rainfall event is 1/20th of our normal rainfall here.
The 2026 obligate-outcrossing seed distribution includes seeds grown by myself and another farmer in Utah, by William in Montana, and for two years by farmers in Kentucky, North Carolina, and two locations in coastal California.
In addition to the selection criteria mentioned already by William, most of the farmers bagged flowers to insure the plants didn’t set seeds without pollinator access. The bagging in mesh organza pouches happened before the first flower in a cluster opened. If any fruits formed on the cluster we culled that plant.
Last year, I planted by sibling groups (seeds from the same plant planted together in a short row). Genetic diversity within some sibling groups jumped out at me. Other families looked like clones. Made it easy to select for outcrossing sibling groups. This year, me and a few other farmers grow these populations as sibling groups.
One intriguing possibility is that if you had a family that looked like clones but the organza bag tests and flower structure were both very correct- you could potentially have a line with all dominant traits. I think that is fairly common in wild SI species. They look uniform but at the genetic level there is quite the party going on. Though that then begs the question: Is an invisible tomato party a fun tomato party?
I am so curious about this guy in the back left of the tray! He sprouted in three days; all of the others were five to nine days. His root system is quadruple the size of the others, and he’s got these interesting purple markings.
Can anyone who contributed to the promiscuous mix tell me what I might have here?
Given its anthocyanin and my love for the Oregon State University anthocyanin tomatoes bred by Jim Myer’s lab- that could be one of mine since I crossed one or two of my anthocyanin lines in my Mission Mountain Series with Joseph’s promiscuous project. Mission Mountain Sunrise was a tomato that performed well for Joseph named Brad x Blue Gold and Mission Mountain Morning was Mission Mountain Sunrise x Joseph’s Big Hill. Very heavy on domestic parents that also did well for Joseph or were his early fully domestic lines. Though fully domestic should have an asterisk as most modern tomatoes have some recent wild ancestry. I use fully domestic here to denote that ancestry as undocumented not non-existent. The anthocyanin traits are an observable marker of a few genes of recent wild ancestry. I love that you have a favorite seedling in the cotyledon stage.
I love your soil blocks. My spouse has taken over my soil blocker for propagating flowers, but I used them for a season or two to propagate vegetables and native plants a little over a quarter century ago. I seem to have lost in that span of time the little plastic cube that made the holes in the larger block for the mini blocks.
This little guy stuck out from the crowd so much, I couldn’t help but take notice of him! And it’s exciting to think that he might be from such multi-generationally intentionally crossed stock. If he ends up being an offspring of one of the crosses you mentioned, what might I assume in terms of growth habit and fruit characteristics? I’m trellising some plants and letting some others sprawl, so I need to decide where to put him.
My first year soil blocking, and it’s working out well… I’m just finding it to be a lot of work. It takes a fraction of the time to press dirt into a 50 cell tray than it does to press 50 blocks. I love the little blocks for germinating, but we’ll see whether I keep using the big ones or just up-pot the little guys into a tray next year. They look nice, though!
I can’t advise you much at this stage of growth. If it shows signs of rugose dwarfism a little later on we’ll know it doesn’t need support. The population has been being selected by me to be eventually rugose dwarf potato leaf anthocyanin bicolors but progress is not complete and these aren’t the most advanced generation.
Penellii are looking good! They are a little slow to get started, and germination seems to continue for a few weeks. I grew them out in 5 gallon pots last year, and though the plants didn’t get very big, they produced all the seed we distributed through the seed share. This year I’m growing some leftover seed from the original GRIN accessions, plus some of my saved seed from last year.
On March 2, I sowed all of my tomato seeds outdoors in covered trays in a mixture of my native soil and a bit of leftover potting mix and perlite. All of them have been germinating nicely in the last week or so!
Profoundly Promiscuous both USA and Canadian collection sown together:
I will be planting all of these tomato plants in separate rows that are side by side, along with other domesticated tomato varieties I have started in a separate tray. Very excited and intrigued to see how things go! I think I might try out two tomato plants per hole to save space and see how well they grow close together, along with one plant per hole to compare results with.
