Backyard Aquaponics
A place to discuss aquaponics

What sort of spacing between plants can you use for lettuce in a AP system compared with a convential garden.

Generally I would plant lettuce at about 30cm centres, in a triangle pattern over the surface of a earth garden.

I would assume that ap systems would allow you to plant closer?

Also what is the difference, if any, in the time to maturity?

It depends on how much nitrogen you have in your system and brow bed size as to how close you can plant your plants. If nutrients are not a problem them you can plant close together. Just remember you cant pull out a plant when its net another without pulling both up. Plant taller plants and let them get a start then plant medium plants under those then plant ground plant under those and prune lower growth of taller plants. I start at 144 carrots per square foot(.3048 square meters).

Ok Dan Fess up! Your carrot appears to be 3" diameter!!!! Unless my math is all mixed up, you could not fit 144 of those babies in a square foot. So do you move them after they get bigger. I'm really interested because that's to be one of my first veggies...

when I plant carrots, I usually seed a heavy row and then as the plants start establishing, I will pull every other seedling if they are touching. As the plants get even bigger, I will pull every other baby carrot for eating and so on until the whole harvest needs to be pulled because they are getting big and tough.

Plant spacing has more than one aspect though. Often dirt garden spacing is based on water/nutrient availability as well as light and air space. Intensive gardening where the soil is heavily enriched/dug etc can get closer together since water and nutrients are being more carefully provided to the plants. Then you get into hydro and aquaponics where water and nutrients have very little to do with plant spacing and it becomes more about how much space the plant physically needs to get enough light and air to thrive. That may to some extent depend on how large you want the plant to get before harvest and what other plants are around it. If you like baby lettuce and baby carrots, they need very little space. If you want full heads, that will be a different story. Or maybe you like both and will thin some to eat as babies while making more space for the others to get bigger.

Oh, and carrots don't transplant well so the 144 (one carrot per square inch) is probably the seeding rate that will require some thinning before the others get big. I would be very careful about planting that density of carrots into an entire grow bed if it is not a half barrel type bed, the carrots would probably burst the bed as they grew. (I have had carrots that I didn't bother to thin, crack open flower pots before.)

That about it TCL you plant heavy and pull out ever other one to make room for growth. A continuous harvest!

As for spacing on lettuce in particular, what variety is of interest? I know romain can grow pretty close together and so can some leaf types but iceburg that one is trying to get heads out of probably needs a bit more space.

In my hydro I was planting lettuces about 3" apart and they definitely crouded eachother and smothered the slower varieties. 6" might be a better distance or do 3" and pull every other one for salad as they start to touch eachother.

Spacing of approx. 6 inch sounds about right, I was looking at leaf lettuce rather than head type.

Do they mature faster compared to a conventional garden in the same area and climate, assuming using bio-intensive method.

So most people use direct seed rather than growing own seedlings?

I am just at design phase of a system and trying to get a feel for what production of veges etc can be expected.

It helps me justify setup costs etc if I can prove to myself that it will save me money, maybe even generate extra over a year or two operation.

start small is my advice. costs can spiral out of control if you don't think small to begin with, and there is a likelyhood of failure initally.
200L tub with 10 goldies and another 200L growbed with gravel with 5x tomatoes in it = perfect first system

Hi Grich
I plant my seedlings about 10cm apart then direct sow seeds all over to the fill the spaces..I start to pick from the seedlings after about 3-4 weeks and the seeds pop up 2-3 days later after sowing. When your system has cycled and nitrates built up you will find your growbed like a jungle. Pick a few leaves and something else will grow up to take its spot. You find one day you pick a leaf of lettuce and a the next day new shoots start popping up. Its amazing stuff.
LB

I sow seed directly into gravel. I have had bad experiences with seedlings from local nurseries. The seedlings often come with pest that later hatch out and devour my crops. This has not been a problem for me when planting seeds.

could you not just measure a full harvested lettuce , then work it out from there ?
I'm of the understanding that given enough nutrients in the system , plants in AP can be MUCH closer than in dirt .
Couldnt it just be worked out so that the fully grown lettuces outer leaves are just touching