Backyard Aquaponics
A place to discuss aquaponics

What type of growing medium works best for very hot weather and i am thinking of building the barrel system they have on here .How would i grow from seeds?

I like hydroton, but it's expensive. I use either lava rock(scoria) or river stone(3/4-1", I think that's 25-40mm? on the bottom, and clay pebbles on the top few inches. You can start seeds directly in the media beds, or use rockwool or seedling trays. A lot of options. Some ar eusing Grow Grips, but I have had zero luck with them germinating.

The larger seeds like lettuce/peas/corn will usually germinate in AP direct.

Smaller things usually have a poor germination rate.

This is my seeding bed:

Colum, you think lettuce seeds are "large"? I guess compared to mustard seeds.

Large in comparison to other things.

They grow very well direct sown, I've tried basil with nothing. Tomatoes are quite hit and miss. But anything bigger than lettuce go well.

I find seeds in AP a bit hit and miss, particularly in warm-hot weather if they don't get enough water.
You have to hand water and/or raise your water level up a bit to keep small roots moist.

I find much greater productivity with all seeds using a simple seed raising stand.
Just runs for 1min 10am and 3pm (twice per day) and I re-use the plastic seed trays I get from hardware/garden store - or else you can buy them very cheap. Use commercial seed raising mix and slow release fertiliser pellets with bit seasol/foliar every now and again.

Germination to plant out rates are very fast and I can bring tomatoes to first flowers and basil, spinach etc much quicker than AP. I then simply transplant into my AP beds and/or wicking beds and re-use seedling trays ready for when first stuff picked.

The seedling stand is only 1.2m x 500mm and fed with overlapping microjets.
Water is caught underneath in a cut down IBC 300mm high sump that I grow duckweed in to add to fish tanks.

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on media I did try cracked pea gravel (a local WA gravel product) but it simply got too hot and also heats up the water returning to the FT. Lost quite a bit of water [edit: to evaporation] keeping water level up high. IMO clay media is best as it also tends to wick up a bit which helps the plants *but* the cost is an issue.

In my buckets and small beds I use gravel at bottom and clay on top - the gravel stays wet all the time.
And the clay is in the flood and drain sections.

http://www.myaquaponics.co.za/french-se ... ool-plugs/
http://www.myaquaponics.co.za/rockwool- ... e-tray-70/

these are two seedling growing trays i found can i use them?and with the rockwool can i put the seeds in and put them in the grow media just like that or should i wait till i have a plant starting to grow