Two basic questions:

huntsman · December 26, 2009

1. If leaves yellow and the plants are treated, does colour return to that leaf?

2. Should one snip off tatty leaves and those that have browned, shrivelled or yellowed?

Thanks...

amideutch · December 26, 2009

If the leaves at the bottom of the plant are yellowing this is normal. Why, as the plant gets into the growth/fruiting phase the nutrients are being used for the new growth and fruits. So less nutrients are available for the leaves at the bottom of the plant. If you have an abundance of nutrients especially nitrogen, then your bottom leaves might remain green. Raybo in his fertilizer tests with his EarthTainers has found some fertilizer's will keep the bottom leaves green where others do not.
As for question 2 the answer is yes. And you can remove the leaves up to the first fruit truss thus making more nutrients available to the rest of the plant. Ami

huntsman · December 26, 2009

Thanks, ami. Much obliged!

Fusion_power · December 28, 2009

All known living organisms exhibit life phases of growth, maturity, reproduction, and senescence. Tomato leaf structures are a microcosm of this process where the leaf grows, matures, grows old, and dies. Even if there is no disease present, the leaf still grows old and eventually will die.

Stress causes leaves to age faster. This can be from a heavy fruit load which consumes photosynthates depriving the leaves or it can be from disease pressure such as septoria or early blight which actively attack and kill the leaves. The longer you can maintain the leaf in prime condition, the more efficiently the plant can complete other process like fruiting.

Most tomatoes are grown with inadequate soil nutrients or with seriously imbalanced nutrients. When you read about a huge tomato plant that produces little or no fruit, that is a huge indicator something was wrong with the soil, likely too much nitrogen. For this reason, I recommend using organic fertilizers that are relatively light on nitrogen or if using chemical fertilizers, use a low nitrogen fertilizer such as 8-24-24 and supplement with a good nitrogen source to balance things out. The objective with feeding your soil is to keep the plant healthy which retains leaves and increases production.

Controlling disease on the leaves is another way of enhancing production. It makes sense that more healthy leaves help produce more healthy fruit. Simple methods like using a pinestraw mulch or spraying with daconil can dramatically improve plant health. Once leaves are seriously diseased it is best to remove them to prevent infection of more leaves from the spores on the dead leaves. Senescent leaves do not have to be removed, but for esthetic reasons, you may prefer to clip them off.

When leaves have yellowed, it is not normally possible to revive them. They have usually exhausted their resources and are on the verge of death anyway. If the plant is fed heavily with a good nitrogen source and if the leaf was yellowing because of nutrient deprivation, it is possible to revive the leaf to some extent. It will not be a young leaf again, but it will produce photosynthates more efficiently and it will turn bright and green. Even so, damage is done by the yellowing process and it will die sooner than a leaf that has never yellowed.

The lesson here is to treat the problem before it becomes visible in the form of yellowing leaves.

DarJones

huntsman · December 29, 2009

Very helpful, thank you!

Is Daconil organic? If not, can you perhaps suggest an organic equivalent?

mjc · December 29, 2009

Quote:

Originally Posted by huntsman

Very helpful, thank you!

Is Daconil organic? If not, can you perhaps suggest an organic equivalent?

No, it isn't.

And a truly effective (on the level of Daconil) organic product does not (and probably never will) exist. There are various organic fungicides that have moderate levels of effectiveness...with lime/sulfur and Bordeaux Solution being two of the most commonly used/most 'broad spectrum' ones available. Neem oil, milk and baking soda have varying levels of effectiveness and may only be useful against a small subset of fungal problems (powdery mildew for instance).

huntsman · December 29, 2009

Ah.

So I'm going to have to prevent rather than cure if I want to stay organic, it seems...

Thanks, mjc!

mjc · December 29, 2009

Quote:

Originally Posted by huntsman

Ah.

So I'm going to have to prevent rather than cure if I want to stay organic, it seems...

Thanks, mjc!

Exactly...improve the soil, manage weeds and work your butt off.

December 26, 2009	#1
huntsman Tomatovillian™ Join Date: Jul 2009 Location: Johannesburg, South Africa - GrowZone 9 Posts: 595	Two basic questions: 1. If leaves yellow and the plants are treated, does colour return to that leaf? 2. Should one snip off tatty leaves and those that have browned, shrivelled or yellowed? Thanks...

December 26, 2009	#2
amideutch Tomatovillian™ Join Date: Feb 2006 Location: Germany 49°26"N 07°36"E Posts: 5,041	If the leaves at the bottom of the plant are yellowing this is normal. Why, as the plant gets into the growth/fruiting phase the nutrients are being used for the new growth and fruits. So less nutrients are available for the leaves at the bottom of the plant. If you have an abundance of nutrients especially nitrogen, then your bottom leaves might remain green. Raybo in his fertilizer tests with his EarthTainers has found some fertilizer's will keep the bottom leaves green where others do not. As for question 2 the answer is yes. And you can remove the leaves up to the first fruit truss thus making more nutrients available to the rest of the plant. Ami __________________ Life's journey is not to arrive at the grave safely in a well preserved body, but rather to skid in sideways, totally worn out, shouting ‘...Holy Crap .....What a ride!' Last edited by amideutch; December 29, 2009 at 12:03 AM.

December 28, 2009	#4
Fusion_power Tomatovillian™ Join Date: Feb 2006 Location: Alabama Posts: 2,250	All known living organisms exhibit life phases of growth, maturity, reproduction, and senescence. Tomato leaf structures are a microcosm of this process where the leaf grows, matures, grows old, and dies. Even if there is no disease present, the leaf still grows old and eventually will die. Stress causes leaves to age faster. This can be from a heavy fruit load which consumes photosynthates depriving the leaves or it can be from disease pressure such as septoria or early blight which actively attack and kill the leaves. The longer you can maintain the leaf in prime condition, the more efficiently the plant can complete other process like fruiting. Most tomatoes are grown with inadequate soil nutrients or with seriously imbalanced nutrients. When you read about a huge tomato plant that produces little or no fruit, that is a huge indicator something was wrong with the soil, likely too much nitrogen. For this reason, I recommend using organic fertilizers that are relatively light on nitrogen or if using chemical fertilizers, use a low nitrogen fertilizer such as 8-24-24 and supplement with a good nitrogen source to balance things out. The objective with feeding your soil is to keep the plant healthy which retains leaves and increases production. Controlling disease on the leaves is another way of enhancing production. It makes sense that more healthy leaves help produce more healthy fruit. Simple methods like using a pinestraw mulch or spraying with daconil can dramatically improve plant health. Once leaves are seriously diseased it is best to remove them to prevent infection of more leaves from the spores on the dead leaves. Senescent leaves do not have to be removed, but for esthetic reasons, you may prefer to clip them off. When leaves have yellowed, it is not normally possible to revive them. They have usually exhausted their resources and are on the verge of death anyway. If the plant is fed heavily with a good nitrogen source and if the leaf was yellowing because of nutrient deprivation, it is possible to revive the leaf to some extent. It will not be a young leaf again, but it will produce photosynthates more efficiently and it will turn bright and green. Even so, damage is done by the yellowing process and it will die sooner than a leaf that has never yellowed. The lesson here is to treat the problem before it becomes visible in the form of yellowing leaves. DarJones

December 29, 2009	#5
huntsman Tomatovillian™ Join Date: Jul 2009 Location: Johannesburg, South Africa - GrowZone 9 Posts: 595	Very helpful, thank you! Is Daconil organic? If not, can you perhaps suggest an organic equivalent?