As a grower I recommend not waiting until your plants are deficient to feed . A steady diet rich in calcium will keep pests from taking over . The stronger the cell walls the harder it is to infest

So sorry for lose thats terrible loss. I had them once they finished my dahlias. I saw them again this year. I used Vinegar with soap it worked

This has been an awful year for so many flower farmers and gardeners. I planted 65 tubers and maybe 25 have grown and some of those are stunted and 3" - 4" tall. Everything is burning up and I left for 1 week and came back to some sort of disease spreading throughout my yard. I haven't had a dahlia bloom yet. 1/3 of my glads grew and bloomed. Ranunculus was pathetic. Lissianthus had a few pretty blooms. Mealy bugs attacked everything. Skeletonizers devastated my grapevine in a few days (but I had bagged the grape clusters this year, so they're still developing). I've tried all the things you've mentioned and I'm about to try BT (but that's expensive). I don't want to use Spectracide Bug Kill (except at the base of my house) even though I know it would kill the spider mites and mealy bugs because it would kill every good bug too (I don't want to hurt any bees or other pollinators). A Master Gardener told me that Gall is in the dirt everywhere and can show up on trees, plants, tubers, etc. It might not have been bad tubers. I had Gall on some dahlia tubers last year that were planted in a plastic tub. They developed the gall after 2 years. Go figure. Jess from Roots & Refuge is learning how to heal her soil (possible Grazon poisoning) after losing nearly all her crops. Skip the plastic bags. You have enough room to simply mound new soil and compost in row. I'd dump the plastic bag soil into a mound somewhere, cover it with a silage tarp for the rest of the year, and then get it analyzed for what's going on with it. Maybe you can heal it so that it can be used in a year or so. Maybe you can grow Crimson Clover on it while you wait. I'm so sorry all this is going on. God Bless You and Your Family. Another thought - can you lift the sides of the hoop house up a few feet higher to provide more air flow?

Ohhhh I am so very sorry my friend, I’m heartbroken for you guys 😔 it’s our worst nightmare as flower Growers to have a whole crop devastated. Last season for us we had hail do it. Thankfully I had enough time left in the season to re sow everything and get something from the season. I wish we were closer, me and my hubby would come and give you a hand to clean it up. Don’t give up, keep going, you have done so well. Now just do what you have to, to salvage what you can. Sending big hugs from us…… I wish it was more!!! Anita 💐💐💐💐

As a full time farmer I would say spider mites are a pretty common problem that we deal with in all growing conditions. Mites are especially known to be a problem in tunnels in many crops including dahlias. I think your best bet it to use a conventional product if you want to save your plants. If you continue to grow in a tunnel you will need to make sure you have a good plan to deal with mites. I've used a product called Portal that worked well in berry crops. Dahlias may not be on the label. You also need to use a good wetting/spreading agent to ensure you have good coverage and really get into the places mites can hide. You need to have great spray coverage when spraying mites. We use Hi-wett super spreader

So so sorry for your troubles. Gardening is like working with terrorists I swear! Prayers for your project! Dahlias are tender.

Spider mites love hot dry conditions and quickly attack weak plants which are out of balance. Excess nitrogen in the plants attacks some pests. They have olfactory senses to detect these plants.

I'm so sorry for your loss I've been using peppermint oil on my dalias and it's been keeping all the pests off them I mix it with water and so far it has been working

I really feel for you. I have lost two very expensive bushes to mites, I lost all my broccoli to white flies and caterpillars, Boring beetles got my cucumbers, fungus has my sweet potatoes and I am having to pick tomatoes early just to save some. Now I am thinking about burning my soil at the end of the year. I really don't know what else I can do.

Oh no,, your poor dahlias ,, it’s a complete disaster ,, it’s your first year in the hoop house and you haven’t any natural predators yet ,, a few things to consider :

I'm so sorry for your loss. I think some of the mistakes you may have made is. 1 Growing Dalhias in a greenhouse. You are containing them into a confine space. This allows all the bad stuff to flourish. If you had grown them outside beneficial insects and mother nature may have keep this from getting out of hand. 2 Using someone else's old soil and bags. God know what was in them bags.

Years ago, I watched a guy on PBS channel who specializes in roses and the like. He always used a tobacco/lemon soap as in dish detergent and he took actual chewing tobacco put in water and added the lemon soap. I think it was ratio of two ounces of tobacco and teaspoon of soap per gallon water. Then let sit at least 24 hours. Strain and spray/ saturate all the plant. It can't hurt!

So sorry to hear that! The trend I’m seeing, on channels with the most success, is growing outside, in ground with that black landscape fabric. You may be able to save some plants and tubers if you transplant, but I’d write off most of that as a loss. Glad you put a claim in! I don’t know if I’d want to rent that place anymore. I do know spiders don’t like peppermint. Glad you know to clean off before going in the house!

Had the same thing happen to my dahlia plants. It happened quickly. One day they were beautiful lots of new buds then in couple days were dead.

Omg, the worst!!! So so sorry 😞 I have spider mites in one if my sunflowers and so fast they just took over. I feel your pain. I'll pray for your hoop🙏

My dahlias were destroyed two years ago because of spider mites. I learned that right when you spot the problem cut the plant and trash it immediately. Then consistently spray. I'm so sorry for your loss :(

So sorry to see the devastation your flowers had. So sad and feel terrible for you and your sweet family. Found your channel a couple of days ago and I just have to say y’all are so inspiring and I am a true fan! Keep smiling and growing those beautiful dahlias! May many blessings come to you and your family!

Maybe treating them for leaf mites before they get infected would help, so the pesticide is already there when the mites show up? I just had to throw away all my Phalenopsis orchids because of a thrip infection, so I know how heartbreaking it is.

Swan island has a video that lists the preventive spray program they use. That may be helpful to check with them to keep this from happening again.

I am sad about your Dahlias, i hope the situation improves for you.