Try again? I thought this sounded familiar. In case you couldn't find your previous posts about this I linked them for you below.

Not sure what more info you are looking for?

With my peat pellets I was able, with fertilizing, to keep seedlings in them for a while until I transplanted (mainly petunias) them in their hanging baskets, could I do the same with plug trays ?

While keeping plants in peat pellets or plug trays that long sure isn't recommended - not only stunts and binds roots but skips the needed fibrous root development trigger that transplanting gives the plant. Why do you want to keep them in the pellets for so long?

But if those issues don't concern you then I suppose you could do the same thing IF you used one of the biggest plug trays. Most plug tray compartments are much smaller than peat pellets are. And the plants will be more difficult to extract from the plug trays. Normally plug trays are just used for germination to the cotyledon stage as they let you germinate multiple plants in each cell and so tons of plants in one tray. Then the plants are separated and transplanted to larger containers. They are not used for growing on.

As to horticubes, as I explained in the previous post, they are used for hydroponics where they will be surrounded by liquids, they are not for transplanting into soil. Rock wool works in a liquid environment but it cannot absorb sufficient moisture or nutrients from soil.

If finding a substitute for the problematic peat pellets is your goal but you want a similar product, why not check out the coconut coir pellets? They eliminate some of the issues with the peat pellets but you still need to strip off the wrapping just as you do with peat pellets and transplant them to an interim container.

Dave

Here is a link that might be useful: previous discussions

Thanks Dave, again, for some great answers ! I wasn't talking about Rock Wool, I was talking about oasis horticubes/rootcubes. I transplant my petunias, that's mainly what I'm growing, at a pretty young stage in their hanging/regular (non hanging) baskets. That works very well for me, cause then I wouldn't have to transplant them twice. I have had great success with peat pellets that way, ofcourse I take of the netting before I plant them in their basket. I don't think that the plants suffer from staying in their peat pellets a little longer. I'm just looking for people that tried these rootcubes and what their experience was. One year I used plug trays and that wasn't a success, but I would like to try it again. My biggest problem then was that I had a hard time watering plug trays. Every year I donate most of my baskets and plants to a local charity to sell, this year I want to double the amount of plants that I want to donate, but I'm running out of space so I was thinking that maybe plug trays or horticubes would save me some space.

Thanks !

Oasis Horticubes are made from a low density foam with rock wool added as a binding agent. The issues are the same as with any rock wool product. The FAQ and product info sheet on their website make it very clear that they are for hydroponic use only.

Similar foam plugs but with out the rock wool component are sold by a couple of other brands - Reddi Rooter is one that comes to mind and the Biodome plugs are another. And the problems they all share in common (several discussions here about them) are (1) how rapidly they dry out if not kept consistently wet and (2) their inability or decompose once transplanted into soil and the resultant root stunting that causes and (3) their lower germination rate. Others have reported pulling up dead plants only to find the foam plug dry and hard even though buried in wet soil.

As already mentioned by not potting up the seedlings are missing a necessary trigger in their growth cycle. But the easiest way to double or triple your production numbers and still use existing space is like commercial growers do it. Just full-seed a 1020 tray (one with holes) and then prick and transplant once they begin to develop true leaves. You can do 200 plants in one 1020 tray and 2" of seedling mix. We do hundreds of different flowers and vegetables that way in the greenhouse every year - including petunia.

Otherwise all I can suggest is order some and give them a try. See if they will work for you.

Dave

Here is a link that might be useful: one of the foam plug discussions

For several years I have been using a product called "Rootrainers". They are in a unit of 32,1&1/2 x 5 inch deep cells which open for easy seedling removal. Regular seed starting or potting mix may be used depending on what you are growing. They may be used up to 10 times before falling apart. Cost is about $18 and is available with or without plastic domes. I have bought them from Lee Valley and Charlies Greenhouse. Al