seedlings not growing - Page 2

berigora · December 20, 2012

Tania, thanks for the tip about coir. It is sometimes promoted in our dry land as a water retentive addition to impoverished soils (and worm farms) so you'd think it would be right to use wherever one needed moist conditions. I think I've gone off the stuff ...

I am now wondering if the seed-raising mix might be the problem with my seedlings especially when combined with my usual practice of putting them in jiffy pots. Perhaps this combination retains water too well! I can imagine too that if one sows during spring when it is warm rather than hot, one would get less evaporation thus a greater chance of water remaining where you don't want it and often don't notice it pooling.

Just as a trial I will repeat all the sowings, some in seed mix and some in potting mix, to see which works better.

berigora · January 16, 2013

I think it is probably the sowing medium. I sowed some Aussie Red and some Mortgage Lifter on 23rd December, half in a generic potting mix and the other half in a good-quality seed raising mix I had not tried before. I put some seeds in punnets, some in flats and some in peat pots.

So far the seeds sown in seed-raising mix have shot ahead and now look like the tomato plants I expected them to grow into. The others are poor stunted little things similar to those described in my original post. The type of container made little difference in the end.

I'll repeat the trial in cooler weather (if we ever get any!) and also over winter with artificial heat and light.

Thanks for your help on this everyone. Your replies really made me think about what I was doing and how to improve on my sowing techniques. El cheapo seed mix? Never again!

JLJ_ · January 16, 2013

It may be that you've resolved your problem . . . but I was interested in Redbaron's post earlier in this thread that referenced having seedlings some times just get "stuck" for no obvious reason.

About three years ago my tomato seedlings did that -- sprouted fine, weren't sick or damaged -- just seemed to be in some sort of time stasis. They remained healthy looking -- but didn't grow. When it was finally warm enough outside, I began to set the flats outside -- with six week old seedlings that looked about six days old -- and in short order they returned to normal growth.

I could think of many things that 'could have been the reason' but the argument against all of them is that those seedlings were in the same location, with the same planting mix, feeding, light, temps, etc. that I have used before and since, which has resulted in normal seedling growth.

That's the only time over the years I've ever had that happen -- seedlings "stuck" with no indications of ill health -- but apparently sometimes they just do that.

Farmette · January 17, 2013

I experimented last year germinating and growing the exact same varieties of seeds in 2 different mediums. One was coir and the other a good quality germinating mix. I had previously always used the germinating mix, but wanted to try the coir as it was cheaper and I just wanted to compare them. The seeds in the coir took several days longer to germinate and grew at a much slower rate. It is true, however, they caught up when planting in the ground. Those that were grown in coir in large containers always continued to be much smaller than those grown in good quality potting mix.

Tracydr · January 17, 2013

Quote:

Originally Posted by KarenO

too cool temps will markedly slow both tomato and pepper growth.

I brought my dwarf tomato inside because of our cold snap this last week. It's been in the dark but despite the dark it doubled in size. I can only attribute it to the warmer night weather, since our nights have been cool, 40 degrees, not enough to kill it but not warm enough to thrive.
I think I'm going to add row cover to all my early plantings from now on!

Tania · January 17, 2013

I also received one more report from my customer using coir based mix, she complained the seedlings were not growing at all.

I think coir mixes are not there yet to trust with our precious tomato and pepper seedlings.

Fusion_power · January 17, 2013

It is more of a user problem than a coir problem. Coir absorbs nitrogen much faster than peat. Coir also holds moisture much better than peat. The result is that you have plants with wet feet and no nitrogen. Add to this that the OP stated they were in dappled shade. The ONLY times it is appropriate to have tomato plants in dappled shade is when hardening them off or when growing them in 110 degree heat.

To use coir, get a PH tester and use it regularly. Adjust PH to 6.5. Get a good high nitrogen fertilizer. Use it twice as often as you would otherwise. With coir, it takes 1 teaspoon of miracle grow 15-30-15 to produce 48 seedlings 8 inches tall. I would recommend applying the fertilizer 4 times as the seedlings are growing with 1/4 tsp each time. Convert the fertilizer to organic versions as needed.

Let the plants dry out until they start to wilt before watering. This is much more important with coir because it retains water. When they wilt just slightly, water them well and then wait until they dry out again before re-watering.

DarJones

Tania · January 17, 2013

Dar, excellent points!

It makes coir mixes harder to work with, compared with peat-based mixes. Many folks (and I am guilty of that too more often than I'd like to

) tend to over-water seedlings, and this aggravates the problem.

Honestly, I started to gently steer my customers away from coir, especially when they are starting from seeds the first time.

Farmette · January 17, 2013

Dar:
Your point about fertilizer is well taken. I was told to water the coir seedlings less than the other. And as my fertilizer was an organic liquid, the coir seedlings got even less fertilizer than those grow in potting mix. So, it is no wonder they did not grow at the same rate. Thanks! Chris

JLJ_ · January 28, 2013

Quote:

Originally Posted by Fusion_power

It is more of a user problem than a coir problem. Coir absorbs nitrogen much faster than peat. Coir also holds moisture much better than peat. The result is that you have plants with wet feet and no nitrogen. Add to this that the OP stated they were in dappled shade. The ONLY times it is appropriate to have tomato plants in dappled shade is when hardening them off or when growing them in 110 degree heat.

To use coir, get a PH tester and use it regularly. . . . DarJones

Do you have a suggestion about a PH tester? I've thought about it, for many uses, and have read a number of threads here and elsewhere, but all I've been able to derive is that most reliable ones are expensive, not only initially, but also in maintenance, requiring frequent replacement of the entire unit or significantly expensive parts -- and that the inexpensive ones aren't reliable enough to be worth the bother. If I buy an expensive tool, I expect it to work well for at least three or four decades, so . . .

RayR · January 28, 2013

All coir is not the same, The PH can be all over the place, it could be under 5.5 up to 7.0. Also salt content is something to be concerned with. Don't buy any old coir like that made for bedding for reptiles, make sure you are getting a coir for horticultural use that is low salt and buffered to a reasonable PH of 6.5-7.0. I'm using General Hydroponics Coco-tek, which is low sodium and buffered to PH 7.0.

January 17, 2013	#21
Tania Tomatovillian™ Join Date: Jan 2006 Location: Anmore, BC, Canada Posts: 3,970	I also received one more report from my customer using coir based mix, she complained the seedlings were not growing at all. I think coir mixes are not there yet to trust with our precious tomato and pepper seedlings. __________________ Tatiana's TOMATObase

January 17, 2013	#22
Fusion_power Tomatovillian™ Join Date: Feb 2006 Location: Alabama Posts: 2,251	It is more of a user problem than a coir problem. Coir absorbs nitrogen much faster than peat. Coir also holds moisture much better than peat. The result is that you have plants with wet feet and no nitrogen. Add to this that the OP stated they were in dappled shade. The ONLY times it is appropriate to have tomato plants in dappled shade is when hardening them off or when growing them in 110 degree heat. To use coir, get a PH tester and use it regularly. Adjust PH to 6.5. Get a good high nitrogen fertilizer. Use it twice as often as you would otherwise. With coir, it takes 1 teaspoon of miracle grow 15-30-15 to produce 48 seedlings 8 inches tall. I would recommend applying the fertilizer 4 times as the seedlings are growing with 1/4 tsp each time. Convert the fertilizer to organic versions as needed. Let the plants dry out until they start to wilt before watering. This is much more important with coir because it retains water. When they wilt just slightly, water them well and then wait until they dry out again before re-watering. DarJones Last edited by Fusion_power; January 17, 2013 at 01:40 PM.

January 17, 2013	#23
Tania Tomatovillian™ Join Date: Jan 2006 Location: Anmore, BC, Canada Posts: 3,970	Dar, excellent points! It makes coir mixes harder to work with, compared with peat-based mixes. Many folks (and I am guilty of that too more often than I'd like to ) tend to over-water seedlings, and this aggravates the problem. Honestly, I started to gently steer my customers away from coir, especially when they are starting from seeds the first time. __________________ Tatiana's TOMATObase

December 20, 2012	#16
berigora Tomatovillian™ Join Date: Nov 2012 Location: Dubbo, Australia Posts: 5	Tania, thanks for the tip about coir. It is sometimes promoted in our dry land as a water retentive addition to impoverished soils (and worm farms) so you'd think it would be right to use wherever one needed moist conditions. I think I've gone off the stuff ... I am now wondering if the seed-raising mix might be the problem with my seedlings especially when combined with my usual practice of putting them in jiffy pots. Perhaps this combination retains water too well! I can imagine too that if one sows during spring when it is warm rather than hot, one would get less evaporation thus a greater chance of water remaining where you don't want it and often don't notice it pooling. Just as a trial I will repeat all the sowings, some in seed mix and some in potting mix, to see which works better.

January 16, 2013	#17
berigora Tomatovillian™ Join Date: Nov 2012 Location: Dubbo, Australia Posts: 5	I think it is probably the sowing medium. I sowed some Aussie Red and some Mortgage Lifter on 23rd December, half in a generic potting mix and the other half in a good-quality seed raising mix I had not tried before. I put some seeds in punnets, some in flats and some in peat pots. So far the seeds sown in seed-raising mix have shot ahead and now look like the tomato plants I expected them to grow into. The others are poor stunted little things similar to those described in my original post. The type of container made little difference in the end. I'll repeat the trial in cooler weather (if we ever get any!) and also over winter with artificial heat and light. Thanks for your help on this everyone. Your replies really made me think about what I was doing and how to improve on my sowing techniques. El cheapo seed mix? Never again!

January 16, 2013	#18
JLJ_ Tomatovillian™ Join Date: Aug 2011 Location: Wyoming Posts: 759	It may be that you've resolved your problem . . . but I was interested in Redbaron's post earlier in this thread that referenced having seedlings some times just get "stuck" for no obvious reason. About three years ago my tomato seedlings did that -- sprouted fine, weren't sick or damaged -- just seemed to be in some sort of time stasis. They remained healthy looking -- but didn't grow. When it was finally warm enough outside, I began to set the flats outside -- with six week old seedlings that looked about six days old -- and in short order they returned to normal growth. I could think of many things that 'could have been the reason' but the argument against all of them is that those seedlings were in the same location, with the same planting mix, feeding, light, temps, etc. that I have used before and since, which has resulted in normal seedling growth. That's the only time over the years I've ever had that happen -- seedlings "stuck" with no indications of ill health -- but apparently sometimes they just do that.

January 17, 2013	#19
Farmette Tomatovillian™ Join Date: May 2009 Location: Wisconsin Posts: 985	I experimented last year germinating and growing the exact same varieties of seeds in 2 different mediums. One was coir and the other a good quality germinating mix. I had previously always used the germinating mix, but wanted to try the coir as it was cheaper and I just wanted to compare them. The seeds in the coir took several days longer to germinate and grew at a much slower rate. It is true, however, they caught up when planting in the ground. Those that were grown in coir in large containers always continued to be much smaller than those grown in good quality potting mix.

January 28, 2013	#26
RayR Tomatovillian™ Join Date: Jun 2010 Location: Cheektowaga, NY Posts: 2,468	All coir is not the same, The PH can be all over the place, it could be under 5.5 up to 7.0. Also salt content is something to be concerned with. Don't buy any old coir like that made for bedding for reptiles, make sure you are getting a coir for horticultural use that is low salt and buffered to a reasonable PH of 6.5-7.0. I'm using General Hydroponics Coco-tek, which is low sodium and buffered to PH 7.0.