How to start salad crops?

[Cameron Smith]

Hello...I'm new to aquaponics. I have a pretty good grasp on the basics...i have a small tank that is nearly cycled and i have a few flowers transplanted and a cucumber sprout looking very hardy and proud. I have lost several herbs and lettuce seeds. I planted them two inches deep to get them watered every cycle. I even sprouted them before planting them, but after more than ten days they have not surfaced.

What is the right way to start salad crops?

[Kevin R.]

I have good luck starting them in seeding trays then transplating once the shoot starts to show first leaves. I have also started seed directly in hydroton but used coconut coir to keep seed from falling through the hydroton into the tank.

[TCLynx]

Yea the water depth can be tricky sometimes for direct sowing of seeds depending on the media and flood height.

I've often had good luck simply sprinkling seeds like lettuce and broccoli, turnips, kale, collards, and others in that family that are really quick to germinate with just a tiny bit of moisture.

However if you are having trouble with small seeds washing away with the flood and drain or not getting the moisture needed while planted shallow enough to surface, you might try making a little wick with tissue or paper towel put edge of paper down to a depth where it definitely gets wet and bury it up to where you want to place the seeds.  Lettuce and brassica seeds germinate just fine right up on the surface provided they stay moist enough.

[Sheri Schmeckpeper]

When I had a timed system, we sprinkled the seeds and had great success. We now have a F&D system with more water activity, so germination is less successful, but still works. I just sprinkle more seeds. That said, I've had success transplanting larger plants like cucumbers, but find the time to pre-sprout lettuce and other quick-sprouting greens isn't worth it.

I sprinkle greens and roots (radishes, beets, turnips). When I sprinkle, I work the media (we use hydroton) a bit so the seeds drop, but I don't worry about whether they all get to the water line. Most will.

[Craig Hannaford]

I start the seeds in a egg carton let them grow for about two to three weeks in a window inside, then transplant them into my aquaponics garden,they seem to be a lot more stable if I grow them that long before I transplant them.

[Bob Campbell]

I'm still trying to perfect this phase too.  I have been sowing directly into pumice and then transplanting.  I'm changing this routine because it's too time consuming to transplant.   Yesterday I planted my seeds in net pots filled with pumice.  The net pots can then be moved to a raft or gravel media.

I recently made a post on blog about seedlings.

I have had problems with Pythium .  I addressed this in the post above, but I'm quite certain the reason I have had such a difficult time is due to the high humidity in my garden room.   I'm working on a solution to that. 

[TCLynx]

I tend to use alot of peat pellets for the seedlings I put into my towers and raft beds (I know not the most sustainable but the spent peat I re-use to make soil blocks so I figure that helps balance the scales some.)  Anyway, I often start seeds for the garden as well and seedlings started in peat pellets and soil blocks can be placed into media beds too.  (I do tend to have lots of media bed for my systems (like 2:1 grow bed to fish tank volume) so a bit of dirt or peat mixed into my media makes little difference in the scheme of things.

I've even done things like make a little trench in my media bed just down to where the media stays wet.  Then I might sprinkle the seeds there (perhaps even with a sprinkling of my sifted worm castings) and leave the trench until the plants are big enough for me to push the media back around their bases.  Heck, some times I just left the trench for the whole crop.

Many things work, it's a well skinned cat so to speak, so try some different things till you find what seems to work best/easiest for you.

[Cameron Smith]

Thanks everybody for the suggestions. If i were to use soil blocks, wouldn't there be a problem with the soil accumulation in my grow bed? I know the peat would be okay to use because it would be worm food.

How is pumice used in aquaponics?

[TCLynx]

Soil blocks is kinda a misnomer since I make my soil blocks from 2 parts spent peat pellets, 2 parts worm castings and one part coir.  All things I happily re-cycle through the worm bins as well.

When I pull old plants out of the grow beds, if there is anything left of the soil block or peat pellet left I usually pull that out of the bed too so it isn't really like I'm creating a huge build up of anything in the beds.

[Cameron Smith]

That's the thing, though. How do they get enough moisture? I like the paper towel idea...something biodegradable that can be used to hold the seed in place deep enough to get wet during the flood cycle, but if they're just sitting on top of the medium, how will they possibly get wet? When I first set up my system, I had my grow bed inlet pipe releasing water about three inches above the surface, so the entire surface would get some moisture on it as the water splashed onto the surface of the gravel. (To sell the idea to my wife, save money by making small mistakes, and be able to manage a system well from the start, I decided to go with a 10-gallon tank and a 10-gallon grow bed--bought the containers for $7 at Lowe's! I know when I get a much bigger system, the splash wouldn't do much to keep the surface moist.) I added a length of pipe to the down spout to prevent the splash because I was losing a lot of water that way as the water was also splashing out onto the carpet in my bedroom! Long story short...the surface of my grow bed is dry. How will my seeds possibly sprout there? 

TCLynx said:

Yea the water depth can be tricky sometimes for direct sowing of seeds depending on the media and flood height.

I've often had good luck simply sprinkling seeds like lettuce and broccoli, turnips, kale, collards, and others in that family that are really quick to germinate with just a tiny bit of moisture.

However if you are having trouble with small seeds washing away with the flood and drain or not getting the moisture needed while planted shallow enough to surface, you might try making a little wick with tissue or paper towel put edge of paper down to a depth where it definitely gets wet and bury it up to where you want to place the seeds.  Lettuce and brassica seeds germinate just fine right up on the surface provided they stay moist enough.

[Cameron Smith]

How does a timed system help sprinkled seeds get moist as opposed to a F&D (I'm assuming you're using a bell siphon? I am, BTW)

Sheri Schmeckpeper said:

When I had a timed system, we sprinkled the seeds and had great success. We now have a F&D system with more water activity, so germination is less successful, but still works. I just sprinkle more seeds. That said, I've had success transplanting larger plants like cucumbers, but find the time to pre-sprout lettuce and other quick-sprouting greens isn't worth it.

I sprinkle greens and roots (radishes, beets, turnips). When I sprinkle, I work the media (we use hydroton) a bit so the seeds drop, but I don't worry about whether they all get to the water line. Most will.

[TCLynx]

In Siphon flood and drain the drain can happen really rapidly so that a seed that managed to get floating in the water might get carried away with the water while timed flood and drain the water levels rise slowly and then they recede slowly so the seeds are more likely to stay lodged in the media.

Lots of small seeds when you sprinkle them, they don't remain on the dry surface but fall down between the dry surface gravel to the moist layer and stick there.  This is why many people will "work" the media after they sprinkle seeds to let them fall down off the surface layer.

[Jim Fisk]

Hi Cameron,

FWIW: I use an extension on my auto siphons to raise the level to just below the media for germination and simply remove it when the roots are long enough. Works great. Keep in mind that I use an Affnan/Bernoulli style siphon with a 2" top so I cut 2" pipe at 1.5 and 2". Same idea should work on most siphon designs. I even supply a set to customers who order more than 1 siphon because I find it handy for lots of reasons even washing and leveling media. Here is a photo of parts for now but I have a pic of it in action somewhere: