seaweed liquid fertilizer (as foliar spray)

If I can spray it on tomato's flower, and is it harmful to human health spraying on vegetables' leaves? (i am a beginner trying to educate myself)

 

hi,

in my opinion, no problem.

Presumably you will use the fertilizer sometime...say weeks... before you are going to eat the vegetables. By this time the fertilizer should have been absorbed and metabolised - otherwise there was no point in using it. If you wash the vegetables before use, any residue that might be on the leaves would be washed off. So the effect on you as a consumer would be the same as with a fertilizer applied to the soil.

Liquid seaweed fertilizers out of the bottle will almost certainly contain bacteria etc and I know in some cases have a preservative added to stop bacterial growth. So probably not a good idea to drink undiluted from the bottle...but otherwise probably very safe !!

ciao
Brian

 

Thank you so much for the answer, i am trying to grow my own vegetables, worrying ..say only leaves vegetables(trying as much organic as i can). i also think that it is much better not to use any spray at all on leaves vegetables, but only soil fertilizer.therefore i plan to use both soil and foliar (organic) fertilizer on fruit plants(tomatoes, zucchini,......etc) but any leave-vegetables.is it a good idea?(as i see you seem to be educated on planting!), thank you very much i hope you can answer a lot of my questions in the future.

 

Hi,
Sorry for not replying sooner. I'm definitely not an expert gardener, but there are lots of very helpful experts in this forum. I can tell you what i do with my vegetables - like you I'm fairly organic but not strict. Before I plant I mix in whatever organic matter I can into the soil (usually garden compost I have made myself). My natural soil is a very heavy alkaline clay. I also add a little chemical fertilizer to the soil at this time (so not very organic). Then as the plants grow I start to use seaweed fertilizer. For example, with zucchini and tomatoes I start to use the seaweed fertilizer when the first fruits are starting to form. But I do not use it as a foliar spray, but add it to my watering can and water the soil. All my vegetables and some of my flowers get the seaweed fertilizer. Here over the summer, I need to water my vegetables every two or three days, but I only use the seaweed fertilizer max once per week. I get good crops doing this - I'm happy with it. I have only used the seaweed fertilizer as a foliar spray "in emergency" when plants are obviously stressed. With tomatoes only say if there are a lot of yellow leaves or when a lot of the leaves show a pattern of green and yellow (say green along the veins and yellow elsewhere). But these emergencies do not happen if I look after my plants properly!! The advantage of a foliar feed is that the nutrients are rapidly taken up and (with luck) the plant recovers really quickly.

To me the big advantage of a seaweed fertilizer is that it naturally contains a wide range of different nutrients - all the ones a plant requires including all the micro-nutrients. Most chemical fertilizer mixes will be deficient in these micro-nutrients. I like to think of the seaweed fertilizer as a "health tonic" for my plants.

Good luck (Boa sorte!)
Brian

 

• Seaweed extracts contain plant growth regulators which, like traditional rooting products, can
stimulate root growth in cuttings and transplants
• Seaweed extracts have no reliable effect on plant production or resistance to disease and
environmental stress, especially in field conditions
• Variations in plant materials and environmental conditions are greater determinants of plant
health than applications of seaweed extract
• Seaweed extracts for landscape use represent a poor use of natural resources, especially those
from environmentally sensitive coastal ecosystems

http://www.puyallup.wsu.edu/~linda ...ltural Myths_files/Myths/Seaweed extracts.pdf

 

Hi Ron,

You will see that in my last email, I emphasised the nutrient content - ie the use of seaweed extracts as a fertilizer. I would agree that the evidence for other beneficial effects is ambiguous. I do not know how seaweed resources are managed in North America, but I do know that in Europe, at least in France, Ireland and Norway, brown seaweed resources are carefully monitored, managed and appear to be sustainably harvested. In Ireland, the country I am most familiar with, there has been continuous significant seaweed harvest for hundreds of years as a source of soda, iodine, fertilizer
and animal feed - all without an obvious negative ecological impact.

Brian