For granular fertilizer it's best to remove the mulch before applying and scratching into the soil (obviously you put the mulch back immediately afterwards). Liquid you can just pour over the mulch.

Rodney

Maybe I'm missing something here. Do you have drip lines in place? Are you talking about impermeable (e.g. plastic sheet) mulch? If not, then anything you throw on the surface is going to be taken up by the irrigation you do and brought to the roots. Seems a waste of time to pick up water-permeable mulch to apply fertilizer. Why does that make sense? I think granular fertilizer is always water soluble. It's not going anywhere. It'll just sit there until the applied water dissolves it, and brings it to the roots. If the water gets to the roots, the dissolved fertilizer will too, along with it. Even putting it under the mulch, it's not getting to the roots until the applied water brings it there. I guess if you want to suppress weeds, you'd rather not fertilize the mulch as well as the soil, but I don't think that's a big deal.

I pull back mulch around base of plant to apply solids, then recover it. I don't scratch the soil surface much, tho, just water it in.

For liquids(seaweed extract & compost tea here) I water over the entire plant, wetting the leaves as well, but not necessarily pulling back mulch. Not sure if that works w/ other liquid fertilizers, tho...

Dan makes a good point - what kind of mulch are we talking about? Assuming a beneficial organic matter mulch then yeah, slip it aside to mix and granular and then I replace it. But with containers I use only liquid supplements mix with their water. With my drip irrigation system fertigation is easy to do. But then I don't use any plastic mulches except on my self-watering Earthboxes.

Dave

In that case, it makes no sense to remove the mulch to fertilize. Just spread the fertilizerYes, on top of the mulch, and sprinkle water on the bed as you would normally do. FWIW, it'll actually help compost the mulch. Yes, not quite all the nitrogen will get down to the roots, but most of it will.

Mulch can insulate in both directions, so won't the dry granules get washed away in a good rain?

Removing the mulch to fertilize in an intensely planted bed for me is not an option. I have 4'x10' raised garlic beds that have 133 plants in each bed with about 4" of shredded leaf mulch. I fertilize with granular urea (46-0-0) about every 10 days with 2 methods. If rain is expected within a day or so I sprinkle about 2 oz of urea per bed between each row using an old spice can and the rain will leach it thru the mulch. If no rain is expected I add 2 oz of urea to 2 gallons of water in a watering can and wait about 30 minutes for the urea to dissolve before watering the garlic. Both methods seem to work equally well. Don't use too much urea with either method or your plants will be scorched!!

But OPs talking mostly of container plants. Different care. Also, generally much less water involved with watering, so that would make a difference.

My wife hogs all of our containers for her flowers so I have no experience on that. I've tried herbs in containers in the past with poor results so I stick with raised or in-ground beds for veggies.

"Mulch can insulate in both directions, so won't the dry granules get washed away in a good rain?"

No. Things get washed away if the water is running off the bed. If the mulch is water--impermeable, and water runs off the bed, the water won't get to the roots. If it isn't tied down somehow, the mulch will get washed off the bed as well. Water won't run off the bed in mulch made of shredded organic matter.

I'm not sure why container plants would make a difference. If the water can get through the mulch to the roots, it'll dissolve the fertilizer and bring it to the roots. If the mulch is so thick that it's absorbing the water before it gets to the roots, that's a whole different problem.

Does it make a difference that I'm using all organic fertilizers? My liquid is fish and seaweed and should go right through, but the granular stuff is probably less water soluble and will take a while to get to the roots...so it will be sitting on top of the mulch for a while. I don't know if this makes a difference. I apologize if that is a silly question. I'm very new to gardening.

I'm not sure which "granular" stuff you're talking about, but ammonium nitrate (which is the nitrogen source in most commercially bagged fertilizers) is crystals that are highly water soluble. For those crystals, it won't make any difference whether they are on top of the mulch or under it. They still need to be dissolved in water to get to the roots.

Just sprinkle it on top of the mulch and water a few times. How much is left there?

Most granular organic fertilizers require soil microbes to eat it and convert it to a form that the plants can use. Potting mixes won't have these microbes typically. I would stick with your liquid fish and seaweed for the containers and use the organic granular in your in-ground beds.

Granular fertilizer, like this stuff? http://www.espoma.com/p_consumer/tones_plant.html#.VTvPWJObjHM I don't think it would work in containers, it is not readily water soluble and needs to be broken down... and it gets moldy and I wouldn't want it touching any plants.

It's similar to that. It's this stuff: http://www.groworganic.com/tomato-and-vegetable-food-4-5-3-4-lb-box.html

It's not very nice of them to put instructions on the box on how to apply to potted plants if it won't work. It confuses newbies like me.

How about when I apply it to the plants in the ground? Over the mulch is fine you think?

Annie, you can use the product in your containers, don't worry. But liquid, soluble fertilizers are used more for containers.

If I'm using a granular fertilizer in my gardens or landscape, I simply broadcast it over the top of the mulch. Rain or a watering will push it through the mulch to the soil.

Annie, don't get discouraged. That's a thing about gardening--there are oodles of different ways to do things. It can be very hard as a newbie because there is so much info, and sometimes it conflicts. And then there's all the factors that are very different depending on where you garden. What works well for me in zone 5 with intense sun, temp fluctuations, and dry climate isn't always going to work for someone zone 5 in the NE with more humidity, different bugs, etc. If you add your location to your profile, it can help--I think it's under advanced settings on your profile page. Add your zone and general location, and it will pop up after your name.

The granular is not terrible or completely unusable for your containers, it just may not be as optimal as a liquid. Granular can work in pots, but it's also possible to wash it out with overwatering or heavy rain when the pots drain, and you may not get all the nutrients as effectively without soil microbes, worms, etc. Of course the manufacturer is not going to tell you not to get their product. So, learn what works for you, and often that includes some trial and error. Also, learning the basics of what the fert numbers mean and what the nutrients mean for your plants is really helpful. If you want more specific assistance, then let us know what you're growing, and the pot size. We know the granular type, but what seaweed liquid do you have?

As Dan says, it makes no sense to remove the organic mulch. Also, said organic mulch, after a couple of years, has provided enough nutrients that only nitrogen is needed (there is a thread in Soil and Compost about someone who added and added OM, and now he has 14 times above optimum P). I add only urea, and urea dissolves in water almost immediately.

But, we're talking first year newbie, mostly containers, not long term in-ground where you should do soil tests to know what you really need. Potting mixes are not comparable, and generally don't contain much for nutrients unless they are enriched, and the mulch is being used for moisture control at this point, not soil amendment. I don't see how such a high nitrogen bump like straight urea will help in this situation.

My first year, I overwatered all my tomatoes, went with more high nitrogen ferts not knowing that phosporus was needed for more bloom and fruiting, and had so-so luck. I over fertilized my beans, under fertilized my corn (i think I got three ears). But I got the gardening bug, stuck with it and spent the next winter learning more--fertilizers, soil amendment, and individual plant needs. What worked great for all my container herbs and veg didn't always translate to the garden plot, and vice versa. It just takes time, patience, and experience.

Thank you all! I'm in Zone 10A. In containers I'm growing blueberries (3nd year in big whiskey barrels), tomatoes, tomatillos, green beans, cabbage, 5 different varieties of hot peppers, spinach, lettuces, beets, green onions, ginger, sweet peppers, strawberries, cucumber, eggplants, basil, stevia, and cilantro. In the ground I'm growing mango, avocado (3rd year), grapes (3rd year), tomatoes, watermelon, zucchini, and more cucumber and green beans. That doesn't include all the stuff that has died. I'm investing more time in containers because of space and things I stink in the ground have a much higher mortality rate (bugs, mammals, or just shriveled up and died). My liquid fertlizer is Neptune's Harvest Organic Fish and Seaweed Fertilizer. My container mix is homemade- coconut coir, compost, and perlite (different mix for the blueberries).

I didn't know urea was a thing. I'm assuming it's a nitrogen source because of the amonia?

I'm also vermicomposting, but don't really know how to use the castings. There's an unpleasant smelling liquid that accumulates at the bottom of my bin. Some people say it's great and I should spray my plants with it and others tell me that it's bad and to throw it away. I don't know what to do...don't want to hurt my plants.

That seems like quite a garden enterprise for a first year gardener. If they're not all bought yet, it may be an advantage to pair down the list. As to the question about worm liquid, I can't give you any info on that.

What type of worm system do you have? Mine is just a tote with holes drilled in, so I rarely get liquid seeping out. Not an expert, but I believe that its very concentrated, so you do have to be careful with spraying or using unless well diluted. It's usually a sign of too wet conditions within (which I also will admit that mine is right now, as I just fed them a bunch of frostbit watermelon discovered hiding in the back of the freezer that didn't get turned into sorbet).

I use my castings by top dressing them on my container plants (mostly herbs). I have also been using them mixed into the mix when potting up my seedlings. Haven't had enough left to make tea from yet, but will probably do that later in summer and sub that for a fish/sea feeding on the herbs, but I'm not personally a fan of spraying.

It is quite a fun list. I'm on my second year with a pair of blueberries myself, but just had to replace one that didn't make it overwinter. What types of containers are you using for all the veg? And, I'll work on getting over jealousy of the tropicals like avocado!

I always remove the mulch and scratch it in the top layer of soil as others have mentioned, and I think it says on the bag. I also do container gardening, but still strive to create an active food web in my mix (and yes, worms do find their way into containers). The reason I remove the mulch is my garden is small so I don't mind and my mulch layer is about 4-6 inches deep so it would take some time for the ferts and things to get down to the roots which is where I want it. I also want to avoid them washing away, because like I mentioned I am container gardening. Secondly, the organic granular fert I use has a bunch of beneficial microbes that I am looking to get into the mix immediately and I really don't want it in my mulch. These microbes break down the fert so it can be accessible to the plants and by doing this it also speeds up composting, basically meaning my mulch will break much faster than I really wanted. I use it for moisture retention. The soil amendment part is just a bi-product for me too. I am sure if I had a large plot on regular dirt I would just broadcast too.

Hi Annie!

YIKES!!! I bow to your courage and industriousness!! You are terrific!!

I have done all these things.Just not all at the same time! From Jax, FL.

I' always pulled back most of the (very deep-4") mulch manually 2-3x/year, depending on the plant, garden, and fertilization schedule.

Florida is a bit different from up home in PA. I cheat. We get an annual calendar from the County Extension folks via the local newspaper. Point being- check with extension agent for your area.Because of the heat, humidity, and rain here, we don't ALWAYS dig into the dirt. Always YMMV- (Your Milage May Vary)