Use a space lift
Lagrange points are too far away from the planet to bother with transfer, especially assuming near-future tech which does not include FTL or handwavium-powered engines. You would lose too much mass of fuel to facilitate building that farm in L1 for example. Instead, you have there a geostationary orbit and already plausible (although not exactly possible) space lift technology, which does not spend fuel in the same amounts as L1 to planet transfer. Remember, fuel spent in space is lost mass for the ecosystem, and on the scale of billions of tons depicted this loss of mass would be noticeable soon enough.
Geostationary, or a tad farther, is still a good place for space farms
Solar flux is what you actually require from a space farm, and while the planet is still close enough to obscure the farm for some time, the general insolation is just a tad less than what you would get in L1 where the planet won't obscure the sunlight entirely. The time difference of daytime vs nighttime even for ISS is positive, also there should (orbit dependent) be times when a satellite's orbit is completely out of the Earth's shadow, with increasing probability as satellites get farther from the planet, as the complete shadow of a planet gets smaller with increasing distance. Thus, a farm placed at geostationary would be lit by the sun about 96-100% of the time per day (depends on the planet's axial tilt). I say negligible difference with L1. And a space lift is a structure naturally extending to that height (or should I say "distance" here?).
Regarding actual flux value, yes a farm at geostationary would get less flux than in L1 because L1 is closer to the Sun, yet since plants have evolved to grow in the lower sunlight than L1's, it could even be beneficial at least for first stages of establishing space farming to not overheat the farm by placing it too close to the sun. However, the Sun-Earth L1 point is 1% closer to the Sun than Earth, thus solar flux in there exceeds Earth's level by 2% (roughly), this doesn't make enough difference to bother. For your planet the value might be different, but a value of 10% corresponds to the planet having the same mass as Jupiter (for the same mass of Sun), thus you can't get more than 1.5x the flux at L1, and what is 50% for such a variable? Build a bigger farm to compensate, anyway you lose a comparable amount to support structures in a space orangery.
You can even have some artificial gravity in there, should your space farm get eventually expanded into complete ring around the planet, which can be then positioned farther than geostationary and aligned for speed with the space lift, making the planet be locally above the space population, with gravity of several hundredths of G provided by centripetal force allowing them to have an up and a down.
And a space lift-tethered space farm does not require space ships to do mass transfer
Instead, you get way more simple mass flow over the space lift, depending on how it would be built or how many lines would it have, you could effectively build a pipe alongside the lift (attention, high pressure!) to allow food turned liquid to be plain dumped down to the planet. Otherwise, any containers that your lift could effectively raise and lower would do.