Slimy liquid from grow bags

[MikA]

Does anyone know why the water passing through my Miracle Grow Organic Choice giant planters degenerates into a green slimy mess, and is it safe to collect the liquid and use elsewhere in the garden?

The bags are cut in half and stood on end with holes spiked 2 " from bottom standing in a gravel tray.

I asked at a local garden centre and the response was not to use the liquid on vegetables but it may be ok for borders. I find this strange as the water has come from the compost in bags being used to grow tomatoes and cucumbers so if what is washing out is not safe to use why is it safe in the bag?

MikA

[Primrose]

I've no idea but it might be worth writing to the manufacturers, asking what material composes the compost, whether they have any idea what is creating the slime and whether there's any risk for using is to water other vegetables.

It could be that if the water is left motionless for any time in the gravel tray it develops algae, in the same way that it would develop in a pond, due to exposure to sunlight. How toxic algae in water is to plants, I'm afraid I have no idea.

[Tony Hague]

Water passing through and out the bottom of your growbags coming out green ? I presume algae, possibly the bag is letting enough light through for algae grow between the bag and the compost, which gets washed out by watering.

Sounds like you are overwatering - if you water until it runs out of the bottom - certainly in quantities enough to be collected for re-use - you are washing the nutrients out of the growbag. Algae also will prefer the wet compost.

Can't imagine the algae causing any harm if you do re-use the water though. They are probably just protecting their nether regions.

[MikA]

Thanks Primrose,


It was indeed a green alga similar as you say to stagnant ponds which have excessive nutrient. It appears the Miracle Grow nutrients are just washing straight out.
We have moved the plants around then emptied and cleaned out the yuk with water. My wife got some Milton to disinfect and rinse the trays before reusing.
Just in case I emptied the water and yuk into a wild area of the garden.

Does anyone if there is a safe algicide to use if this starts to happen again.

Tony - I deliberately gave a lot of water as we were away for a few days but the weather was dull and cool so presumably not much used. Lessons will be learnt.

MikA

[peter]

Soil bacteria on a lettuce = dire rear.
On a flower = so what.

[Primrose]

I don't have a greenhouse or a gravel tray on which to rest my plants but for watering purposes I tend to stand all my pepper & other plant pots on the patio, either in individual saucers or on a long tray so that surplus water can drain into that. Sometimes if the compost gets fairly dry, although some of the water drains out fairly quickly, over the course of a couple hours, capilliary action causes it to be soaked up again and the water isn't wasted. If that doesn't happen, I drain off the surplus water which obviously does contain some of compost's nutrients, and reuse it to save wasting it.

The saucers also act as a well for water retention if we're away for two or three days and the weather is warm, in which case, for a limited period I've found that them sitting getting their feet wet really doesn't seem to do them much harm. On one occasion when we were away for about 8 days I left my peppers in a tray of surplus water in a shady place and on our return there was still a little water in the tray. The peppers were fine and there was no algae in the water. I suspect it's the fact that they were in bright sunlight that caused the problem.

[MikA]

Hi Primrose,

I've been taking some time to try to alleviate the problem. My greenhouse is actually on the patio outside the back door (another story) so I don't want too much yuk dripping everywhere. I think next year (hopefully) I will use pots, as the on-end growbags with holes 2" up for drainage do not allow any excess water to be soaked back up.

I have moved the bags into individual gravel trays and am trying to water little and often. I am also using an old turkey baster to suck the excess out of the trays.

There is a distinct difference between the composts in the bags.

The Miracle Grow Organic Choice giant planter is by far the worst offender and is the one that has caused the algae problem. I may even move the one of my two cucumber plants out of its bag into a pot with a fill of different compost as it is falling behind the one transplanted into a pot directly. (This one was due to go outside).

I will post another topic later to give comments on composts I am using.

MikA

[Primrose]

There is a distinct difference between the composts in the bags.

The Miracle Grow Organic Choice giant planter is by far the worst offender and is the one that has caused the algae problem. I may even move the one of my two cucumber plants out of its bag into a pot with a fill of different compost as it is falling behind the one transplanted into a pot directly. (This one was due to go outside).

MikA

I had this problem with my tomato seedlings growing in New Horizons Peat Free compost. Some of them started to look very sickly so I transferred them into pots of a soil based compost & they immediately started to pick up. A think a lot of us are having problems with compost these days. There seems to be no general standard or benchmark and often it can be the luck of the draw. Even if you use the same brand from year to year the quality seems to vary enormously.

[Johnboy]

Hi Primrose,
You have managed to hit the nail on the head good and hard.
You may have noticed over the last few months I have repeatedly suggested that there should be a British Standard for Non-Peat Products.
As you say batch to batch and year to year these non-Peat products vary so much nobody knows which to buy for the best.
If a British Standard was introduced with a Kite Mark on on every bag and the government were not so hell bent on banning Peat before a really proper alternative, which is truly consistent, things would be a whole lot different for the gardening public.
JB.

[Primrose]

JB - I do agree, and with more people now starting to grow their own vegetables, I would have thought the whole question of benchmarking ought to come higher up the national agenda. I'm sure a lot of vegetable growing novices just give up after their failures to raise decent seedlings when often it's nothing to do with their inexperience, but the quality of the compost which has led to their disappointments. One would have hoped that some of the leading voices in the horticultural industry would get together and start lobbying the government to get something done.

[Tony Hague]

What do you suggest should be the test/standard ?

Should it involve a germination rate test ?
Should it be a standard relating to the ingredients of the compost ?

I can see the point, though I suspect it will be difficult to implement. The ingredients are likely to be variable from year to year - it is made of recycled rubbish, remember, over which you have incomplete control, rather than a predictable material like peat.

What I think is lacking are decent seed composts. It is difficult these days to find specialist seed composts - even peat based JI seed compost - at all in the average garden centre, let alone a peat free one. It seems to me that a finer graded, more consistent product, possibly in smaller bags at a premium price, just for seed sowing, would help a lot. There seems to be much less argument about the performance of existing peat-free composts for growing on ?

I am certain something suitable could be made from all the leaves that get cleared up each autumn - leaf mould seems to make quite a nice seed compost.

[MikA]

Tony

In my case I used J A B John Innes seed - soil based compost from last year to sow in and Westland Multi-purpose + JI 55% peat to grow on. The seeds germinated fine and grew on well. They are also growing reasonably well in the growbags but a couple of tomatoes are showing signs of stress. I can't tell if they are short of food because it's washing through, incorrect watering or just the colder weather at the moment which is slowing them down.

Why is nobody mentioning reduced peat compost. Surely this is a possible way to reduce peat use by gradually increasing the non-peat element without going ott. with a total ban before a consistent safe alternative is available.

Edited - how do I get smilies in?

[Johnboy]

Hi MikA,
Simply click on the Smilies that appear on the LHS as you are writing and they come across automatically.
JB.