Melons and watermelons in southern Finland

[JesseI (Jesse Ilonen)]

I sowed my melons and watermelons (all that is covered with black plastic) a couple of days ago (25.5). The weather has been really favorable for them, besides that it’s been extremely dry. The highs have been often over 25C (76F) so it’s maybe not as much cold tolerance in the beginning, but that might change. It’s still been around 5C (41F) at ground level, besides the last few days that it’s been around 10C (50F). This year I’m not using cloth to help, even if they would need it (possibly barring some freak hard late frost). I just hope there is the right amount of cool and warm weather. Black plastic does help quite a bit already.

Seeds are mostly from last year, with some seeds from @ThomasPicard and some from the year before. I was planning of making a big mix, but had some seeds that I wanted to sow preferentially. Mostly seeds from fruits that had little seeds or that had been the very top performer. Those are sowed only the same seeds in a small area or made a smaller “premium mix” that I oversowed. Mostly still sowed 20-30 seeds per hole and in some cases 100 or so. Especially older seeds and melons I oversowed a lot. I’ll cull extras periodically. In the end there is room for 1 plant per 2 wholes so it’s going to be quite a battle for survival.

[WojciechG (Wojciech Górny)]

It is extremely fascinating to see how we differ in our methods and trials
I have received watermelon seeds from three of GTS members in our European exchange.
I have sown 3-3-4 seeds from this pool. All 10 seeds have germinated. I have planted seedlings in deep straw mulch and now I will forget them until the possible harvest
My space is very limited, and I focus on other veggies and fruits, thus such small numers. Deep mulch is the only way I can battle extreme heat and draught we have now, black plastic would have been a disaster without irrigation. This spring is the driest I remember, and vegetation is over three weeks faster than normally. I think I will be slowly switching to dry farming in my cool temperate (in theory) climate.
Good luck with your trials Jesse.

[ThomasPicard]

@WojciechG

It is extremely fascinating to see how we differ in our methods and trials

+1

@WojciechG

black plastic would have been a disaster without irrigation.

I have a very different experience with tarps (black or green) on non irrigated land, and nearly no input, with all cucurbits including watermelons, and notably in 2022 when there was an all-summer long drought: water was kept under and I harvested about 4kg/m² on watermelons and 2 to 3.5kg/m² on the others (3.5 being maximas). This year I use partially tarps on a similarly non irrigated land, sanding soil… with the worst ph I ever had: 4.5-5!!!..

@WojciechG

This spring is the driest I remember, and vegetation is over three weeks faster than normally.

The exact contrary here: anual average rains is about 800mm here, but we have had nearly about that amount over the mid-october mid-march period, and… yesterday marked the day when the May rains exceeded 250mm!!! Crazy… Just for one month + cold temperatures (maximum 20, usually daily max around 15). Everything slow, late.

Eventually I will direct sow cucurbits later than @JesseI ! Would have rotten in the ground otherwise

[JesseI (Jesse Ilonen)]

Both melons and watermelons are starting to emerge. More melons than watermelons, but they tend to be 1 day faster in general. So far it looks like there aren’t going to be too many empty areas, if any, because of germination. Bug damage or weather might change that. Hopefully more will come up so I don’t have to rely on lone survivors.

Because of the hot weather they are still at the same pace as last year even without cloths, and although it will cool down, it doesn’t look to be cooling down so much that they would be growing at a slower pace than last year. Might be the opposite, but remains to be seen. Still good to get some more normal weather to get some selection pressure towards cool tolerance.

Watermelons

Melons

[JesseI (Jesse Ilonen)]

Now they are up in numbers. A lot better than last year. Few spots there are less, but that probably is due to there being fewer seeds to start with. The fastest are starting to make the first true leaves. Thinned a little bit of the slower or faulty seedlings, mostly melons that I probably oversowed more heavily. Two more hot days and after that it doesn’t seem it’s going to go much over +20C (68F) as far as the forecasts go. That’s just good so that I get some selection in normal weather. Hopefully there won’t be too much nasty weather. Some forecasts have shown even highs of just over +10C (50F).

Like last year there have been some seedlings that either have been cut under soil or have rotted. Not that many compared to the total numbers and there is mostly still a lot of excess even after some culling. Last year there were fewer seedlings and in the end the damage wasn’t too bad which is why I’m not too concerned. maybe it’s something they can or need to adapt to.

[JesseI (Jesse Ilonen)]

It’s been a rough week for melons and watermelons. They have been decimated but not obliterated. Last time it was above 20C (68F) was last weeks thursday. After that it’s been briefly at 19C (66F), but mostly highs at or just over 15C (59F) with rains lowering temps frequently more. What probably has been too much for them is the cold nights, some nights just above freezing, which lowers the ground temp and days aren’t warm enough to warm it back up. First I thought it’s too much water, but looking at the ground it’s actually fairly dry. It was so dry to start with that it only is making up for the lack of water.

It’s still touch and go where the situation will develop. Both melons and watermelons look to have enough seedlings to even have extra going forward, but it’s uncertain if more damage will become evident in the coming days. Especially watermelons look a bit uncertain as they have less extras. I’m guessing that it wont be a complete disaster in terms of getting the area covered with plants. Might be that it’s a bit patchy. Luckily weather will warm up to highs at 20C (68F) or above and warmer nights atleast for time being. Doesn’t look like there is going to be many hot days, but should be enough to make them comfortable.

If weather wasn’t enough, as insult to injury some rodent had almost completely eaten seedlings from one row (or half row). It’s probably because it is next to the grass and there was easy access to under the plastic. Fortunately that wasn’t the most important row. It had seeds from 2022 and some seeds that I saved from F1 varieties last year. Some plants have survived so far so have to keep fingers crossed that it had enough.

Some of the most affected melons.

Some of the better melons. It looks like they have even grown during the last week.

Some of the damaged watermelons and one of the better ones. Damage to watermelons isn’t as evident. Many are quite badly wilted and will probably succumb in the coming days. Even if they survive, it’s likely that they wont recuperate. There are still many that look like there isn’t anything wrong. The best have clearly grown albeit just a little.

[JesseI (Jesse Ilonen)]

Finally the situation with melons and watermelons is becoming more clear. As I expected, there were many plants with damage deeper down that either died after last update or didn’t show sings of speedy recovery and were culled.

In watermelons there are 2 outliers that never showed any signs of stress or damage and even continued to grow during the cooler period. They are now about the same size as the best last year and have time to make several fruits. Then there are sort of secondary outliers which were at least stunned by colder weather, but which also started to grow rapidly after it warmed up. Those are around 10-15 days behind and just barely have time to make ripe fruits.

Melons did overall a lot better, but also those had spots were all were wiped out. There weren’t clear outliers, but clearly some seeds (had sown from same seeds in blocks) had more plants that weren’t affected. Best are about the same speed as last year. Average plants are about a week behind and just should have time to produce. Some plants in both melons and watermelons are left even if they don’t have a realistic change to make fruits just to possibly donate pollen.

As there were long stretches were there weren’t anything likely to produce, I made something I usually don’t do and moved some of the good enough plants, which otherwise would have needed to be culled, to those spots. I do not expect much from them. Maybe they make some fruits or at least donate pollen. I moved them after the last heatwave and after that it’s been quite ideal conditions for them to recuberate.

Now it’s a bit cooler again with highs staying under 20C (68F), some days just barely over 15C (59F) with light rains and overcast weather. Nights atleast are warmer than in june and I’m not expecting any damage from cold. It’s interesting to see if they still continue growing during the period. It’s supposed to warm up next week and at least then the growth should pick up.

Best watermelon.

“Normal” good watermelon. Many plants are within few days of growth of these.

Best melon. There are probably around 10 that aren’t too much behind this one.

More common sized melons.

[JesseI (Jesse Ilonen)]

Made a “timelapse” of biggest melon and watermelon plant to see how they grew during colder period. It’s not been too cold, highs still around 20C (68F), but it’s been rainy and overcast which has kept the temperatures cooler. Growth is clearly visible even between days (also growth of the weeds and their demise). Not all pictures are taken at the same time of the day which is why growth between pictures can vary due to different time period. Still growth in the last picture is probably due to the best weather for growth in the last week with high of 23C (74F) and mostly sunny. Rains are still expected in to continue, but temperatures should be higher up to highs of 20-25C (68-77F). Growth should explode now. Biggest plants have female flower buds visible, but flowering is still some days away. Last year watermelon had first flower 8.7 and melons just before mid month. Mid month is still good timing, but anything later than 20.7 is pushing it.

[JesseI (Jesse Ilonen)]

First female flower on melons opened a bit sooner than expected and day or two earlier than last year. Although there aren’t clear signs that others, besides second plant from the same seeds, would join the party in the next couple of days. Might have missed some ofcourse. This one I pollinated with probably 10 different flowers from 10 different plants. Plant itself is fairly big at the time of flowering. Ideal would be that it started flowering earlier on a smaller plant that stayed compact. On the other hand, being big and still flowering earlier than some plants that might be more compact tells that it has faster vegetative growth. Having first flower this time is early enough to have all fruits ripen within the season probably 90% of the years. It’s still not fast enough if I remove the black mulch which I’d like to do at some point. That probably will delay flowering 7-10 days and needs a little more cold tolerance. And that’s on a year like this. Colder summer is still uncharted territory. Still years to go before it’s a staple crop here, but this seems good initial selection towards that goal.

[ThomasPicard]

First flowers in my “early melon” patch today too!!! And even 2 female flowers! All are direct sown melons on the 5th of June. Pollinated with a few male flowers too. Seeds will be mostly for you and other northerners.

[JesseI (Jesse Ilonen)]

If you can pollinate them with something from me, that would be great. I think just about all from your melon seeds died in the cold period and those that survived aren’t doing great. In watermelons one of the better plants was from your seeds, but otherwise not many survived. It’s a bit rough here even if it’s fast to produce elsewhere. Still remains to be seen how many will survive this deluge. Atleast it’s supposed to be fairly warm that the plants can use up the water. Thanks for thinking about us in the north

[ThomasPicard]

Thanks for these infos. Interesting. And I’ll do that. I will also wait for the plants originating from your seeds to make their first female flower to pollinate the other way. I may be wrong (nothing serious to definitely back that up) but I believe the choice of the mother plant could be crucial : mitochondrial things and microbiome being tranfered by the mother plant through seed, only genetic info (which is for sure super important) being shared through pollen. Could be another topic in itself if we had something to back that up, or precise it.
Overall I mean that the plants from your seeds may have “what” mine don’t have to thrive in Finland, and if it wasn’t genetic, choice of mother plant would be crucial.
Anyway I’ll try to do both ways, so by next year we know for sure what’s important and what’s not.
As expected, going the other way round, from north to south, all your plants doing good in here (from moschatas to tomato crosses, eggplants, etc.). Nonetheless we’ve had one of the worse growing season ever (cold, rainy) so this season is not relevant to really assess transfers from Scandinavia to Mid or South Europe.

[JesseI (Jesse Ilonen)]

There are too many things that matter to pursue each individually. Just have as wide crossing as possible and probably something will stick. Luckily melons usually make a lot of seeds, and if you don’t concidere that it’s taking some from growing edible flesh, it doesn’t have such downsides as seedy watermelon for example. Maybe at some point I’ll concentrate on smaller seed cavity and less seeds in melons too, but right now surviving is the main priority and having a lot of seeds helps to find those that have what it takes here whatever it might be.

[JesseI (Jesse Ilonen)]

First female flower in watermelon surprisingly wasn’t in the 2 best plants, but this little fella. It also has an interesting trait of having several male flowers close to the base. It’s a useful trait as male flowers tend to be hard to come by when the first females open. This one I could pollinate with the best plant that had just opened it’s first male. It seems to concentrate more on growing, but females shouldn’t be that far away. They are clearly visible on several of the vines. Ideally they would be open by now, but there is still about a week to open and have a decent change of making them ripe. Anything later than that probably not going to be as good to eat, but might still have viable seeds. Hard to say how many will eventually make it. At least many need to be fast to open females or males if they want to contribute. Weather isn’t too bad for them. A bit too wet, but atleast warm. If they get going they can do a lot in 10 days.

Best melon now opened second flower and some more are showing. Second plant from the same seeds also opened it’s first flower. Some others are also only days away. These two I also pollinated with flowers from several dozen different plants. Same applies to melons regarding time to get female flowers with the exception that melons at least can contribute pollen more easily.

[JesseI (Jesse Ilonen)]

Yesterday also the biggest watermelon had first flower open and it looks like there might be some more open even today, or at least in the next couple days. The first flower to open was in the second biggest vine and it looks like all the vines have fairly uniform flowering which would be a good trait. The flowers were quite small and consequently fruits are likely to be small to medium. Doesn’t really matter at this point. The plan is to at some point divide the population into summer strain with small fruits and storage strain with medium sized fruit with good storage. This fruit I pollinated with the 2 other plants that had flowers, but because those had already partially closed, I also selfed this to make sure.

[JesseI (Jesse Ilonen)]

The first melon is starting to size up. Others look like they have been pollinated and might start to grow any day now. Watermelons still don’t have any growing. It looks like the first flower on the best plant was not properly developed and did not start to grow. Now there has been 2 flowers open on consecutive days that looked much better and more to come. Hopefully they pollinate now when there is still fairly good time to grow. Next week looks like weather will be ideal for melons and watermelons as much as it ever is here. Sunny with highs just over 25C (77F) and fairly warm nights. Anything that flowers this week is still likely to make seeds, but after that the window will close fast.

[JesseI (Jesse Ilonen)]

Finally first watermelons are growing. It’s a bit late, but unless there is some unexpected weather next month, all should at least ripen seeds. Not betting on getting fully ripe and tasty fruits, but that’s ok if i just get seeds. Hopefully they will improve next years success. First one to start to clearly develop wasn’t on either of the top performers after june, but one of the secondary stand outs which started growing like crazy after it got through the cold period. Also the top performer has now finally kept at least 2, with 2 more looking like they are about to grow and one more just pollinated. There are over 10 fruits total that look like they have started to grow and some more that will get confirmation in the next few days. Might still be quite a good number of fruits if all goes well. I have used top performer to pollinate all fruits in the other plants, and inversely, used all flowers I could find in other plants to pollinate top performer to get the maximum diversity, but skewing towards the top performer. Next year is going to be interesting.

In melons the first to flower for some reason has not started to develop other fruits even though there are several that look pollinated, but are not developing or dropping. The one fruit is going to be big though. Little more than 2 weeks after pollination it’s already around 700-800g (by sight) which is average for me. Probably will be 1,5kg-2kg, but might be even heavier. Other plants are also making fruits, some even several. It’s only in the last few days that there has been more flowers open. If all goes well all pollinated by now will at least ripen seeds. So far I have manually pollinated them like with watermelons, expect using several of the top performer to mostly pollinate others and vice versa. Pollinators ofcourse do their job, I just try to skew the results towards what I want. Should be quite a diverse mix.

Early next month I’ll see which plants are carrying fruits and remove others if they are in the way. At that point should see better how many fruits I have in total.

[JesseI (Jesse Ilonen)]

It’s starting to be late season for melons. Usually they get something in their leaves some time in august. This time it seems to be caused by the rains. So far I haven’t seen any evidence that there would be something tolerant to this. There is a little variation in how badly they are affected, but even the best look still quite bad.

There are about 6 plants which have fruits that were pollinated a month ago or close to and will make seeds by all likelyhood. For the others prognosis is not as clear. There are a few maybes and more which are unlikely to make even viable seeds. It’s still not a complete wash. Even in the worst case I’ll have a lot of variance. Also it’s good that melons do make (usually) a lot of seeds. Even around 10 fruits is still plenty of seeds

First to flower decided it only want’s to make one fruit despite many flowers clearly pollinating. Maybe not getting as huge as I thought, but it still looks like it’s closing to 1,5kg mark. White one behind is from the same seeds. Slightly smaller fruits, but there are 3 of them.

This one has little too cracked skin to my liking and but at this stage, and especially this year, anything that makes seeds is welcome. Can choose against this trait once there is more to choose from.

This one made one big fruit fairly fast to a small vine. It wasn’t the best looking in early growth, but speed is the key. Not really hoping mine to make more than 1-3 and instead have more plants to make total yield good.

This one had fairly skinny starts of the melons and only recently they have gotten fatter.

One of the fastest to flower. It didn’t hold the first fruits and is a bit behind, but should have just enough time finish seeds.

This one got accidentally to watermelon side and happend to be one of the best. Only one fruit, possibly because it’s next to a very thick bean bush.

Interesting late developer. Haven’t had anything that would be this thin at the start. With how the leaves look it seems unlikely that it will even make seeds, but one can hope. At least it showsh the possibilities.

Watermelons still look good in their leaves, but that’s about to change sooner or later. They still have more to go than melons and wouldn’t still say they will make viable seeds. Even that would need a couple
of weeks more. Weather forecast doesn’t look too bad for that. There are about 15 fruits that clearly have started to grow, but not all are growing well. Might be that there are still some damage in the roots from early season. I’ll take it even if they make tiny seedy fruits this year and work on them the next years.

Best plant, which was a couple days later to hold fruits as the first, has now clearly overtaken the first to start growing fruit. This one has bigger fruits 2 that are clearly growing and one more tennis ball sized that isn’t growing very well, but it can remain to produce seeds if it just stays. This plant looks like it has some siberian sweet in it, but fruits are even paler green. Also nice to have the yellow type survive. it was one of the best last year and this type had the fastest ripening fruit a couple of years ago.

First to hold fruit is still growing well. It must be 3 weeks from pollination now so it will still get to a good size.

Couple of different skin colours. At least the first looks like one of the ones I got from Spain. Second also is similar, but might be something else.

A few with moons and stars heritage in them. Didn’t direct sow straight from those seeds so this must be from a pollen donor. Fruits aren’t developing very fast; these started just after the bigger fruits. Anything that makes seeds is welcome still.

[Hugo (Hugo Morvan)]

Hi Jesse. What do you mean when you say bad weather? Nightfrost or nights under 10 or something?

[JesseI (Jesse Ilonen)]

I considering it to be fairly good this time of the year if days are around 20C and nights don’t get much under 10C. And not too much rain. But that’s setting the bar quite low. Not ideal for melons and watermelons. It already starts to be quite wet with longer nights and often morning mists which might hang around until midday. So even if tecnically day highs and night lows are “good”, other features of the weather makes it challenging. Last year was the first time both of them clearly survived to september, the last succumbing around 10.9. Even then it wasn’t that cool, but compination of the temperature, a lot longer nights with a lot of moisture and diseases was too much. I suspect late season might be quite similer there too, just a month or so later.

Luckily right now there is going to be at least 4-5 warmer days with highs up to 25C. After that chances of that kinda warm days get’s slimmer, but at least at the moment there aren’t any long cold periods in sight that could kill the plants in days.