Garden Plants - When to harvest?

I use this guide all the time. I usually try to graft onto plant's that can be harvested in 18-24 hours. Makes it simpler for me.
http://www.carls-sims-4-guide.com/skills/gardening/

a "24 hour" plant doesn't mean you'll get the maximum harvest in 24 hours, it's just a rough estimate of the time the plant takes to start producing harvestables. It takes a fraction of that time for the plant to produce more harvestables afterwards.

As for there being any sort of visual queue, I think looking at the plants is supposed to give you an idea. The maximum you can ever harvest is 10.

Also, the number of petals on the picture next to the name of the plant doesn't affect the number of harvestables on the plant - its just an indicator of when the plant will be ready to evolve to the next quality level

Sometimes when I am unsure if I’ll get a full harvest I go into build mode and put one of my plants in my inventory. I always undo after but this will tell you how many are available to harvest at the moment.

"Hermitgirl;c-16460824" wrote:
I use this guide all the time. I usually try to graft onto plant's that can be harvested in 18-24 hours. Makes it simpler for me.
http://www.carls-sims-4-guide.com/skills/gardening/

I timed 24 hours on a plant that is listed as 24 hours and didn't get the full harvest.

"NorthDakotaGamer;c-16460825" wrote:
Hover over the plant. There will be a flower over it. Wait to harvest until all the petals are shown.

I thought about that but one of the plants isn't harvestable but shows all petals:
http://i21.photobucket.com/albums/b291/Poliwag/Plasma%20Tree_zpsa0cnccae.jpg?t=1525259797

"Poliwag;c-16460848" wrote:

"Hermitgirl;c-16460824" wrote:
I use this guide all the time. I usually try to graft onto plant's that can be harvested in 18-24 hours. Makes it simpler for me.
http://www.carls-sims-4-guide.com/skills/gardening/

I timed 24 hours on a plant that is listed as 24 hours and didn't get the full harvest.

"NorthDakotaGamer;c-16460825" wrote:
Hover over the plant. There will be a flower over it. Wait to harvest until all the petals are shown.

I thought about that but one of the plants isn't harvestable but shows all petals:
http://i21.photobucket.com/albums/b291/Poliwag/Plasma%20Tree_zpsa0cnccae.jpg?t=1525259797

Nah that just the leaves of the plasma fruit tree. It's showing glowing fruits when it's ready to be harvest. Other sides note of this tree the fruit can go bad and pulsing like a heart when not harvested after a while.

"Madachan88;c-16460882" wrote:
Nah that just the leaves of the plasma fruit tree. It's showing glowing fruits when it's ready to be harvest. Other sides note of this tree the fruit can go bad and pulsing like a heart when not harvested after a while.

(Another edit, NorthDakotaGamer is the one that said that once the flower has all petals it is fully harvestable)

I know it isn't harvestable, that's why I used that tree. The tree shows as having all petals on the flower (the happy flower picture) but it has no fruit.

Edit: I just picked an onion plant that had the flower with all petals and only got 2 onions.

There has to be some way to find out when to pick, rather than waiting a whole day after they first start producing *sighs*

I usually don't have trouble with the 24 hour ones. I don't time it though and make sure to try it exactly 24 hours later. I usually get a full harvest (if I care about doing that). If the plants look full it's time to harvest them.

I have another program open so I couldn't go in to take a picture. But in this picture I found, you can see a rose bush, lily bush and tulip bush ... all with some flowers. None of them are full yet though.. so if I harvested them .. it looks like I might get about 2 from the tulip.. maybe 4 or 5 from the rose and maybe 3 or 4 from the lily plant. The rest aren't flowering yet at all (they might have been recently harvested). I know in this picture she's still skilling up her gardening and I haven't started splicing. If you keep gardening and playing at it you get to know when by looking at them.
The reason I splice them is they all come in about the same time that way. None of these plants are spliced yet..

"BossLady0309;c-16464211" wrote:
Sometimes when I am unsure if I’ll get a full harvest I go into build mode and put one of my plants in my inventory. I always undo after but this will tell you how many are available to harvest at the moment.

Oh yeah, that's a great idea! Thanks :D