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Dracaena leaves turning black - any help?

Posted by ah97 (My Page) on
Fri, Aug 6, 10 at 3:08

Hi,

I've had the Dracaena plant for a year with no problems. I give it 500 ml of tap water, once every week.

Lately, the leaves started getting black areas and the tips turning black as well.

Any help is appreciated!


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RE: Dracaena leaves turning black - any help?


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RE: Dracaena leaves turning black - any help?

  • Posted by tapla z5b-6a MI (My Page) on
    Fri, Aug 6, 10 at 9:39

While it could be fungal (doubtful), or from over/under-watering, simply adding a pint of water weekly absolutely guarantees a steadily progressive build-up of soluble salts in the soil. This is the main reason such a high % of hobby growers think houseplants 'only last a year or two' before you have to buy another that doesn't look so ratty.

You haven't given us anything to go on, as far as cultural conditions and your fertilizing/watering habits, but based only on odds, my first guess is you need to take steps that will eliminate both soluble salts AND the possibility of root rot if you DO water properly.

Al


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RE: Dracaena leaves turning black - any help?

Thanks Al. Can you or someone please advice on
- what is the correct watering habit for such a plant?
- how often should I add a fertilizer?
- how often should I replace the soil?
- how to eliminate a soluble salts and root rots.

Thanks.


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RE: Dracaena leaves turning black - any help?

  • Posted by tapla z5b-6a MI (My Page) on
    Sat, Aug 7, 10 at 10:50

Here is a synopsis of the easiest route to long term good vitality in your plants, and for plants you can pass down to your children if they want them:

If you cannot water so that you fully saturate the soil every time you water, and a fair % (at least 10-15%) of the total volume of water you applied exits the drain hole - your soil is inappropriate. OR, you need to take steps to ensure salts do/can not accumulate. Flushing the soil on a regular basis (at least every 2-4 weeks) is very helpful in keeping salt levels at a reasonable level, but flushing the soil doesn't address the aeration/compaction associated with soils so water retentive you cannot water properly w/o risking root rot.

The best way to water is to apply enough water so the soil is thoroughly moistened. Then, return a few minutes later and apply enough water so that at least 10-15% of the total volume you applied in both applications flushes through the soil and exits the drain. During this watering, your pot should be where it can drain freely or it should be above a saucer so the soil never comes in contact with the effluent after it has exited the drain hole.

How often you fertilize depends on where the plant is in its growth cycle, what your soil is like, and your watering habits, so no one can tell you how to fertilize w/o knowing something about these things. Because I use soils that drain freely, I fertilize weekly at half to full strength in the summer. Those plants I over-winter under lights get fertilized every time I water, but at low dosages. I usually add 12 drops of Foliage-Pro 9-3-6 fertilizer to a gallon of water (winter) and fertigate with that solution. The plants always have a low dose of the proper ratio of nutrients available in the soil. Coming full circle to the fact that we WANT to keep salt levels low, you can see how frequent low doses of fertilizer and a soil/watering regimen that flushes salts from the soil before they accumulate is very beneficial.

Plants vary, but most plants are physiologically constructed so they can be bare-rooted and repotted on a regular basis. When to repot sort of depends on your goals or your vision for the plant, but base your decision on the fact that when the root/soil mass becomes congested to the point that you can lift it from the pot intact, growth has already been negatively affected and the growth rate/vitality will continue to decline. Even if you pot up (as opposed to repotting) you will see only the plants temporary return to a growth rate a little closer to its potential, but you will never see its full growth potential restored unless you correct the original root congestion.

I would suggest you repot at the point the root/soil mass can be lifted intact, or the year after that milestone in the month before your (house)plant will exhibit it's most robust growth. I repot all my houseplants & tropical/subtropical trees in late Jun to early Jul, unless I fall behind, which often occurs because of the number of plants I have.

You asked about how to avoid root rot. Very important is to keep your plants growing robustly - a plant that has good metabolism is manufacturing plenty of the bio-compounds that allow the plant to resist these fungi. Second, avoid the cultural conditions that allow these fungi to grow/multiply. Avoiding soils that support a soggy layer of soil at the bottom of the pot ("drainage layers" do not help) is key. Proper watering habits and avoiding high soil temperatures is also helpful.

Once you understand a few basic principles that apply to an extremely high % of plants, maintaining your plants so they always exhibit good vitality and a healthy appearance is easy. When all is said and done, the source of what binds most people down and prevents them from being able to realize the full potential of their containerized plants is the soil. Usually, watering issues, appearance, even disease and insect infestations can all be traced to low vitality levels that have their roots in the growers choice of soil.

Admittedly, light, fertility, temperature ..... also play major parts in whether or not your plant will realize its potential, but each of these conditions are easily changed by the grower in an instant, but the effects of a poor soil persist, setting you down slope from an uphill battle from the outset.

Al



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RE: Dracaena leaves turning black - any help?

Hi,

Can anyone tell me if it looks like same issue? I have just recently repotted the plant with new potting mix and the issue started. I planted other dracaena plant in the same mix but those seem to be doing fine. Can anyone please advise how to revive this plant?

Thanks


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RE: Dracaena leaves turning black - any help?

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Thu, Sep 11, 14 at 16:56

It's hard to say for sure. If it started immediately (within a month or 2) after the repot, it might be from anoxia (not enough O2 in the soil due to compaction or (most likely) a soggy soil. It could also be related to the accumulative effect of fluoride in foliage tissues or a high level of dissolved solids (salts) in the soil. If you're interested in chasing it further, you'd need to tell us more about your growing habits so we could weed out the more unlikely causes.

Al


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RE: Dracaena leaves turning black - any help?

Not all tap water is equal, but *most* tap water can make Dracaenas ill. Any of the common substances in tap water seem to be offensive, fluoride, lime, chlorination.

Even if not possible every time a plant is thirsty, giving (and flushing) with pure water can help a lot. Rain, distilled, and condensate from dehumidifier or A/C are good sources of pure water (in a plant sense, don't drink condensate.)


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RE: Dracaena leaves turning black - any help?

Massangeanas are more or less guaranteed to lose leaves this way. Or at least they are from the tips.

The brown patches half way up are less usual, and almost look like it got either sprayed with something or caught by a sudden increase in sunlight?


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RE: Dracaena leaves turning black - any help?

It started right after repotting repotting. I use tap water but I also let it sit for 24hrs to evaporate the Chlorine. It was a perfect plant before repotting. I have more of the same potting mix. Do u think re potting again will help? If it is lacking O2 can I put some peroxide it the soil...3% h2o2 diluted in water


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RE: Dracaena leaves turning black - any help?

Also it only received indirect sunlight. It has been at the same spot as it was when it was healthy. I have trimmed the brown parts but not sure how to cure it.


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RE: Dracaena leaves turning black - any help?

Personally I'd leave it alone then.

I'm of the "let sleeping dogs lie" school when it comes to repotting. :-D


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RE: Dracaena leaves turning black - any help?

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Mon, Sep 15, 14 at 18:28

Most chlorine (chloramine) additives no longer gas off if you leave your tapwater open to evaporation, and fluorine just doesn't gas off at all. Adding the H2O2 will add some oxygen to the soil, but it will also produce free -O radicles that will oxidize the first organic molecule they contact, so it's not a good long term remedy. The damage is almost surely related to hypoxia (not enough O2 in the root zone) or fertilizer burn, and in looking at the picture I'm getting the gut feeling that it's not enough air in the roots. Repotting into the same soil will likely produce the same results, and trying to manage your watering so the soil doesn't get too wet will result in a build-up of dissolved solids in the soil, which also inhibits water uptake and produces the same spoiled foliage.

I could link you to a thread that will help you deal with excess water retention, or you could investigate making a soil that you can water to beyond saturation (so your flushing the soil when you water) w/o having to worry about what you're dealing with now.

Al


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RE: Dracaena leaves turning black - any help?

Thank you everyone for advice...


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RE: Dracaena leaves turning black - any help?

Hi Tapla what thread were you recommending?


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RE: Dracaena leaves turning black - any help?

  • Posted by tapla z5b-6a mid-MI (My Page) on
    Mon, Sep 15, 14 at 21:29

Here's the thread that will help you deal with excess water retention in your soils.

More important though, is knowing how to avoid the excess water retention, poor drainage and insufficient aeration entirely. You can read about that here.

Please let me know if you have questions or want guidance.

Al


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RE: Dracaena leaves turning black - any help?

Thank you for the link...Tapla


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