As far as seed quantities, I always assumed that 'seed' was a unit of seed needed to seed a square of land. Hence why you would get one 'seed' from a strawberry: enough to perpetuate itself in an equal or slightly greater amount of space.
You underestimate the sheer number of plants from which we eat the seeds, or just don't discard the seeds...
You pick the seeds out of your strawberries?
Rice and other grains and grasses.
Sesame Seed.
Soy Beans (and any soy product).
Corn and anything made from it.
Cucumbers.
Watermellon (well, I do anyway).
Pumpkin and other gourds/squashes.
Tomatoes.
Amoranth.
Pepper (the fruit-type. Capsicum).
Pepper (the pepper-corm type. Piper).
Dill.
There's also pleanty of things which we eat long before it produces seed, destroying the seed-bearing structures. Examples:
Cabbage and it's kin (kale, brocoli, brussel sprouts... all same species, just selected for different traits.).
Lettuce.
Many Herbs. Most, in fact.
Raddishes, carrots, and other root-fruits.
So to have a more realistic seed/plant system, we really would only need 4 factors. Currently we have 2: GROWDUR and SEED, and the assumption of seeds produced on processing. We could, instead, have the following:
1. MATUREDUR: amount of time plant needs to grow before it can be harvested.
2. EATDUR: Amount of time after Maturedur has ellapsed in which it can be picked for food.
3. SEEDAGE: after this time, will produce seed upon being processed.
4. MAXAGE: after this time, plant is considered dead.
So I have three hypothetical plants.
1. plant eaten only before it goes to seed: MATUREDUR 300, EATDUR 100, SEEDAGE 500, MAXAGE 550. So it will mature at 300, be edible from 300-400, then be inedible as it goes to seed, produce seeds at 500, and the plant itself dies at 550.
To make sure that this plant is not eaten before going to seed could just require something as simple as a modification to the Kitchen Extended Options (which I have proposed, as a way of gaining all the versatility but keeping it simple for those that do not want 10 options to set per plant), that lets one specify whether to harvest every plant, every other plant, no plant, or say 'harvest on seed' vs 'harvest at maturity' to simply only pick it once it has gone to seed, or merely once it is ripe for eating or use.
2. Plant which produces seeds at the same time: MATUREDUR 400, EATDUR 100, SEEDAGE 400, MAXAGE 500. Will be both mature and produce seed at 400, and will die at 500.
3. Plant that produces seed only if harvested late: MATUREDUR 400, EATDUR 100, SEEDAGE 475, MAXAGE 500
Other flavorful additions: SEEDON, SEEDNUMBER, USEON, SEEDEAT, SEEDMILL, ect.
SEEDON would have two options: PICK, AUTO, and PROCESS. PICK would only leave viable seeds when the plant was picked between going to seed and MAXAGE. If the plant dies, no seed. AUTO would be it automatically drops a seed when it goes to seed, which can be picked up by farmers and stored. Since the seed is dropped automatically, the plant can live or die as is seen fit. PROCESS only gives seed when the plant is processed. Make sure to only put this on plants that are still processable when able to produce seed. If a plant has SEEDON:PROCESS but makes a seed long after MATUREDUR has expired, SOL. If a plant has SEEDON:PROCESS and SEEDON:AUTO, then it will produce a seed at a particular time automatically, and a second seed when processed.
SEEDNUMBER would set a min and max number of seeds. SEEDNUMBER:1:2 would mean min 1, max 2. If I wanted a plant, for example, that produced hundreds of seeds, SEEDNUMBER 100-200. This may sound insane, but if I have a plant that is harvestable for food really quickly, but takes all year (literally) to produce seeds, it actually evens out play-wise. Also, it makes it so, if you want, SEEDNUMBER:0:1 could ensure that there is only a 50% chance of getting a seed. Another modification could be to have a bell curve function similar to the bell curves used in personalities. SEEDNUMBER:1:10:3 would generate a stereotypical bell curve with a maximum at 3, thus one might occasionally get a large cluster, but most likely it will be 2, 3, 4 seeds.
USEON would be a flavorful thing to add, as it would allow the use of the plant to change with time. Example: USEON:300:400 would mean that between 300 and 400, it would be usable for the next argument (example, MILLDYE). USEON:500:550 could make the same plant be usable for, say, brewing between the times of 500 and 550. Based on the way raws are set up, though, this USEON argument might need a USEONEND like in Basic code, to signal when that particular USEON argument ends.
SEEDEAT says whether the seed is edible or not. If, for example, you want a plant, like Rice, where it is the seeds themselves that are edible, you could have the following: MATUREDUR:500, SEEDDUR:500, SEEDON:PROCESS, SEEDNUMBER:25:50, SEEDEAT, but have no arguments for what it is processed into, it will basically 'process' the plant, producing no usable processed stuff, but producing 10-20 seeds, and it is these seeds which are eaten or planted as Armok sees fit. This is perfect in conjunction with the thing someone else mentioned, of having 5 seeds be worth one ingredient, because the seed needed to seed a square could be enough to feed half a family. It would be good, if that system is implemented, to have cooks be able to carry bags of seeds to the kitchen, lest the seeds be horribly time-consuming to have. Any plant without SEEDEAT will not produce edible seeds. Example, you don't (well, shouldn't) eat apple seeds, and I think few people probably eat Mango pits (I should look that up later to be certain).
SEEDMILL is as it seems: like when milling plants, but the seed can be milled. Again, good if joined with the other guy's 5seeds per ingrediant thing, because every 5 units of seed could go to a unit of flour.
One thing I am confident in, is Toady's ability to sit down, think everything through, and come up with a system that works nicely, is generally more, or still, streamlined, and adds fun (both types) and complexity to the game. I can only ever hope that the suggestions I give help him out...